The separate and combined effects of MHC genotype, parasite clone, and host gender on the course of malaria in mice.

BACKGROUND: The link between host MHC (major histocompatibility complex) genotype and malaria is largely based on correlative data with little or no experimental control of potential confounding factors. We used an experimental mouse model to test for main effects of MHC-haplotypes, MHC heterozygosity, and MHC x parasite clone interactions. We experimentally infected MHC-congenic mice (F2 segregants, homo- and heterozygotes, males and females) with one of two clones of Plasmodium chabaudi and recorded disease progression. RESULTS: We found that MHC haplotype and parasite clone each have a significant influence on the course of the disease, but there was no significant host genotype by parasite genotype interaction. We found no evidence for overdominance nor any other sort of heterozygote advantage or disadvantage. CONCLUSION: When tested under experimental conditions, variation in the MHC can significantly influence the course of malaria. However, MHC heterozygote advantage through overdominance or dominance of resistance cannot be assumed in the case of single-strain infections. Future studies might focus on the interaction between MHC heterozygosity and multiple-clone infections.

Mechanisms of reproductive isolation between an ant species of hybrid origin and one of its parents.

The establishment of new species by hybridization is difficult because it requires the development of reproductive isolation (RI) in sympatry to escape the homogenizing effects of gene flow from the parental species. Here we investigated the role of two pre- and two postzygotic mechanisms of RI in a system comprising two interdependent Pogonomyrmex harvester ant lineages (the H1 and H2 lineages) of hybrid origin and one of their parental species (P. rugosus). Similar to most other ants, P. rugosus is characterized by an environmental system of caste determination with female brood developing either into queens or workers depending on nongenetic factors. By contrast, there is a strong genetic component to caste determination in the H1 and H2 lineages because the developmental fate of female brood depends on the genetic origin of the parents, with interlineage eggs developing into workers and intralineage eggs developing into queens. The study of a mixed mating aggregation revealed strong differences in mating flight timing between P. rugosus and the two lineages as a first mechanism of RI. A second important prezygotic mechanism was assortative mating. Laboratory experiments also provided support for one of the two investigated mechanisms of postzygotic isolation. The majority of offspring produced from the few matings between P. rugosus and the lineages aborted at the egg stage. This hybrid inviability was under maternal influence, with hybrids produced by P. rugosus queens being always inviable whereas a small proportion of H2 lineage queens produced large numbers of adult hybrid offspring. Finally, we found no evidence that genetic caste determination acted as a second postzygotic mechanism reducing gene flow between P. rugosus and the H lineages. The few viable P. rugosus-H hybrids were not preferentially shunted into functionally sterile workers but developed into both workers and queens. Overall, these results reveal that the nearly complete (99.5%) RI between P. rugosus and the two hybrid lineages stems from the combination of two typical prezygotic mechanisms (mating time divergence and assortative mating) and one postzygotic mechanism (hybrid inviability).

Pratique en cas de lactogénèse insuffisante

L'installation de la lactation et l'allaitement durable suivent des processus délicats. Pour différentes raisons, souvent complexes, la production de lait maternel peut diminuer. Des moyens galactagogues peuvent alors être proposés. Les auteures ont tenté de mieux cerner la palette de moyens galactagogues utilisés par les sages-femmes de Suisse dans leur pratique quotidienne. L'enquête a fait l'objet d'un poster au Congrès d'Appenzell en mai 2009 qui a été classé au 2e rang.

Chemical and carbon isotopic evolution of hydrocarbons during prograde metamorphism from 100°C to 550°C: Case study in the Liassic black shale formation of Central Swiss Alps

Hydrocarbon distributions and stable isotope ratios of carbonates (delta(13)C(car), delta(18)O(car)), kerogen (delta(13)C(ker)), extractable organic matter (delta(13)C(EOM)) and individual hydrocarbons of Liassic black shale samples from a prograde metamorphic sequence in the Swiss Alps were used to identify the major organic reactions with increasing metamorphic grade. The studied samples range from the diagenetic zone (< 100 degrees C) to amphibolite facies (similar to 550 degrees C). The samples within the diagenetic zones (< 100 and 150 degrees C) are characterized by the dominance of C-< 20 n-alkanes, suggesting an origin related with marine and/or bacterial inputs. The metamorphic samples (200 to 550 degrees C) have distributions significantly dominated by C-12 and C-13 n-alkanes, C-14, C-16 and C-18 n-alkylcyclopentanes and to a lesser extend C-15, C-17 and C-21 n-alkylcyclohexanes. The progressive C-13-enrichment (up to 3.9 parts per thousand) with metamorphism of the C-> 17 n-alkanes suggests the occurrence of cracking reactions of high molecular weight compounds. The isotopically heavier (up to 5.6 parts per thousand) C-< 17 n-alkanes in metamorphic samples are likely originated by thermal degradation of long-chain homologous with preferential release of isotopically light C-1 and C-2 radicals. The dominance of specific even C-number n-alkylcyclopentanes suggests an origin related to direct cyclization mechanism (without decarboxylation step) of algal or bacterial fatty acids occurring in reducing aqueous metamorphic fluid conditions. The regular increase of the concentrations of n-alkylcycloalkanes vs. C-> 13 n-alkanes with metamorphism suggests progressive thermal release of kerogen-linked fatty acid precursors and degradation of n-alkanes. Changes of the steroid and terpenoid distributions are clearly related to increasing metamorphic temperatures. The absence of 18 alpha(H)-22,29,30-trisnorneohopane (Ts), the occurrence of 17 beta(H)-trisnorhopane, 17 beta(H), 21 alpha(H)-hopanes in the C-29 to C-31 range and 5 alpha(H),14 alpha(H),17 alpha(H)-20R C-27, C-29 steranes in the low diagenetic samples (< 100 degrees C) are characteristic of immature bitumens. The higher thermal stress within the upper diagenetic zone (150 degrees C) is marked by the presence of Ts, the disappearance of 17 beta(H)-trisnorhopane and thermodynamic equilibrium of the 22S/(22S + 22R) homohopane ratios. The increase of the alpha alpha alpha-sterane 20S/(20S + 20R) and 20R beta beta/(beta beta + alpha alpha) ratios (from 0.0 to 0.55 and from 0.0 to 0.40, respectively) in the upper diagenetic zone indicates the occurrence of isomerization reactions already at < 150 degrees C. However, the isomerization at C-20 (R -> S) reaches thermodynamic equilibrium values already at the upper diagenesis (similar to 150 degrees C) whereas the epimerisation at C-14 and C-17 (alpha alpha ->beta beta) arrives to constant values in the lower anchizone (similar to 200 degrees C). The ratios Ts vs. 17 alpha(H)-22,29,30-trisnorneohopane [(Ts/(Ts + Tm)] and 18 alpha(H)-30-norneohopane (C29Ts) vs. 17 alpha(H),21 beta(H)-30-norhopane [C29Ts/(C29Ts + C-29)] increase until the medium anchizone (200 to 250 degrees C) from 0.0 to 0.96 and from 0.0 to 0.44, respectively. An opposite trend owards lower values is observed in the higher metamorphic samples. The occurrence of specific hydrocarbons (e.g., n-alkylcyclopentanes, cadalene, hydrogenated aromatic compounds) in metamorphic samples points to kerogen degradation reactions most probably occurring in the presence of water and under reducing conditions. The changes of hydrocarbon distributions and carbon isotopic compositions of n-alkanes related to metamorphism suggest that the organic geochemistry may help to evaluate the lowest grades of prograde metamorphism. Copyright (c) 2005 Elsevier Ltd.

Analisi espacial del canvi climàtic al continent europeu. Incerteses i exposicions principals

El canvi climàtic del segle XXI és una realitat, hi ha moltes evidències científiques que indiquen que l’escalfament del sistema climàtic és inequívoc. Malgrat això, també hi ha moltes incerteses respecte els impactes que pot comportar aquest canvi climàtic global. L’objectiu d’aquest projecte és estudiar la possible evolució futura de tres variables climàtiques, que són el rang de la temperatura diürna a prop de la superfície (DTR), la temperatura mitjana a prop de la superfície (MT) i la precipitació mensual (PL_mes) i valorar l’exposició que poden experimentar diferents cobertes del sòl i diferents regions biogeogràfiques del continent europeu davant d’aquests possibles patrons de canvi. Per això s’han utilitzat Models Climàtics Globals que fan projeccions de variables climàtiques que permeten preveure el possible clima futur. Mitjançant l’aplicatiu informàtic Tetyn s’han extret els paràmetres climàtics dels conjunts de dades del Tyndall Centre for Climate Change Research, del futur (TYN SC) i del passat (CRU TS). Les variables obtingudes s’han processat amb eines de sistemes d’informació geogràfica (SIG) per obtenir els patrons de canvi de les variables a cada coberta del sòl. Els resultats obtinguts mostren que hi ha una gran variabilitat, que augmenta amb el temps, entre els diferents models climàtics i escenaris considerats, que posa de manifest la incertesa associada a la modelització climàtica, a la generació d’escenaris d’emissions i a la naturalesa dinàmica i no determinista del sistema climàtic. Però en general, mostren que les glaceres seran una de les cobertes més exposades al canvi climàtic, i la mediterrània, una de les regions més vulnerables

Nanotermoparells: heterounions de nanowires

Projecte de recerca elaborat a partir d’una estada a la University of California a Irvine, EEUU, entre juliol del 2007 i gener del 2008. Els termoparells són actualment els sensors de temperatura més populars i més utilitzats per a un ampli rang d’aplicacions: industrials, domèstiques, etc. Aconseguir miniaturar els dispositius fins a dimensions extremadament petites obra un ampli rang de noves aplicacions per aquests dispositius, per exemple, en el camp de la tecnologia lab-on-a-chip. En aquesta investigació, el concepte de termoparell, és a dir, dos cables de diferent metall connectats per un extrem s’ha extrapolat a l’escala nanomètrica, utilitzant nanowires com a element de construcció. Aquests nanowires s’han sintetitzat a través d’un nou procediment desenvolupat en el grup d’investigació de la Universitat de California, Irvine, que ha permès treballar amb nanowires de diferents dimensions (control independent de l’alçada i amplada) i un major grau d’èxit en la fabricació d’aquests termometres. El mètode també permet dipositar aquestes nanoestructures sobre substractes no conductors de manera controlable, simplificant notablement tot el procés de fabricació. L’obtenció d’aquests dispositius ha permès demostrar que, a part de ser bons sensors de temperatura a nivell macroscòpic (fonts de calor ambientals), també permet la determinació de temperatura a nivell microscòpic (fonts de calor focalitzada, com és el cas de feixos làser). Per a la seva caracterització ha estat necessari l’ús de tecnologia puntera (làsers, amplificadors, microscopis de forces atòmiques) i inclòs el disseny de nous dispositius. Aquests nanotermoparells presenten propietats extraordinàries, com una gran sensitivitat, gran velocitat de resposta a estímuls tèrmics, i un comportament estable vers l’ús i el temps.

Community ecology of the metazoan parasites of white croaker, Micropogonias furnieri (Osteichthyes: Sciaenidae), from the coastal zone of the State of Rio de Janeiro, Brazil

One hundred specimens of white croakers, Micropogonias furnieri (Desmarest 1823) (Osteichthyes: Sciaenidae) collected from Pedra de Guaratiba (23&deg;01'S, 43&deg;38'W), State of Rio de Janeiro, Brazil, from September 1997 to August 1999, were necropsied to study their parasites. The majority of the fish (95%) were parasitized by metazoan. Twenty-eight species of parasites were collected. The nematodes were the 40.5% of the total number of parasites specimens collected. Dichelyne elongatus was the most dominant species. Lobatostoma ringens, Pterinotrematoides mexicanum, Corynosoma australe, D. elongatus, and Caligus haemulonis showed a positive correlation between the host's total length and parasite prevalence and abundance. The monogenean P. mexicanum had differences in the prevalence and abundance in relation to sex of the host. The mean diversity in the infracommunities of M. furnieri was H=0.499±0.411, with correlation with the host's total length and without differences in relation to sex of the host. One pair of ectoparasites showed positive covariation, and two pairs of endoparasites showed positive association and covariation between their prevalences and abundances, respectively. Negative association or covariations were not found. The dominance of endoparasites in the croakers parasite infracommunities reinforced the differences found in sciaenids from the South American Pacific Ocean, in which the ectoparasites are dominant.

Proteinuria de rango nefrótico y nefroangiosclerosis. Características clínicas y evolutivas diferenciales.

La proteïnúria de rang nefròtic (&3g/24h) sol considerar-se secundària a una malaltia glomerular. Coincidint amb altres autors hem observat que alguns pacients amb biòpsies renals indicades per proteïnúria de rang nefròtic han estat diagnosticats de nefroangiosclerosi hipertensiva (NAS-HTA). Presentem un estudi retrospectiu en el qual descrivim les característiques clíniques i evolutives d’aquests pacients en comparació amb pacients amb proteïnúria de rang nefròtic d’altres etiologies. Concluïm que s’hauria d’incloure la NAS-HTA en el diagnòstic diferencial de la proteïnúria de rang nefròtic. L’absència d’edemes i una albúmina normal serien un indicador clínic diferenciador amb altres patologies que cursen amb proteïnuria de rang nefròtic i podrien servir d’ajuda en la presa de decisions quan la realització d’una biòpsia renal és controvertida.

A Proportional Approach to Bankruptcy Problems with a guaranteed minimum

In a distribution problem, and specfii cally in bankruptcy issues, the Proportional (P) and the Egalitarian (EA) divisions are two of the most popular ways to resolve the conflict. The Constrained Equal Awards rule (CEA) is introduced in bankruptcy literature to ensure that no agent receives more than her claim, a problem that can arise when using the egalitarian division. We propose an alternative modi cation, by using a convex combination of P and EA. The recursive application of this new rule finishes at the CEA rule. Our solution concept ensures a minimum amount to each agent, and distributes the remaining estate in a proportional way. Keywords: Bankruptcy problems, Proportional rule, Equal Awards, Convex combination of rules, Lorenz dominance. JEL classi fication: C71, D63, D71.

Genes as leaders and followers in evolution.

A major question for the study of phenotypic evolution is whether intra- and interspecific diversity originates directly from genetic variation, or instead, as plastic responses to environmental influences initially, followed later by genetic change. In species with discrete alternative phenotypes, evolutionary sequences can be inferred from transitions between environmental and genetic phenotype control, and from losses of phenotypic alternatives. From the available evidence, sequences appear equally probable to start with genetic polymorphism as with polyphenism, with a possible dominance of one or the other for specific trait types. We argue in this review that to evaluate the prevalence of each route, an investigation of both genetic and environmental cues for phenotype determination in several related rather than in isolated species is required.

Tractament amb EPOCH a dosi ajustada i Rituximab en pacients no tractats amb LNH-B de cèl.lula gran de mal pronòstic

Aquest estudi multicèntric, fase IV analitza l’eficàcia i la seguretat del tractament amb dosi ajustada d’EPOCH amb Rituximab en infusió continua, en pacients no tractats prèviament amb mal pronòstic diagnosticats de limfomes B de cèl.lula gran. Material i mètodes. S’inclogueren 81 pacients, 68 d’aquests diagnosticats de Limfoma B difús de cèl.lula gran, 7 de Limfoma fol.licular grau III i 6 de Limfoma B primari de mediastí. Eren pacients de mal pronòstic segons IPI≥2 o IPIae≥1, ECOG/PS 0-4, estadi II-IV (estadi I si malaltia voluminosa al diagnòstic). Resultats. La edat mitjana era de 52 anys (rang, 21-77 anys), 92,5% d’alt risc segons l’IPIae. Es va obtenir resposta completa (RC i RCi) en el 79% dels pacients, la supervivència global i la supervivència lliure d’esdeveniment, a la mediana del temps de seguiment (34,3 mesos) va ser de 68% i 63,2%, respectivament. La supervivència lliure de malaltia als 5 anys va ser de 72,2% pels pacients que van assolir RC/RCi. Cap dels factors de risc de l’IPI o IPIae, ni els índexs per ells mateixos van resultar amb associació estadísticament significativa a la OS o PFS. Només es va obtenir associació entre els nivells de ß2 microglobulina (&3,5mg/l) i la PFS i OS (p=0,075 i p=0,015, respectivament). Es van reportar 54 episodis de neutropènia febril (11,5% dels cicles); i es van morir 27 pacients, 15 (55,5%) degut a progressió de la malaltia i 9 (33,3%) degut a sepsi o infecció grau 4. Conclusions. Els resultats aconseguits amb la combinació de Rituximab i DA-EPOCH mostren uns resultats prometedors i amb nivells de toxicitat molt acceptables en els pacients d’alt risc diagnosticats de Limfomes B de cèl.lula gran no tractats prèviament.

Hemispheric asymmetry and theory of mind: Is there an association?

Introduction. In autism and schizophrenia attenuated/atypical functional hemispheric asymmetry and theory of mind impairments have been reported, suggesting common underlying neuroscientific correlates. We here investigated whether impaired theory of mind performance is associated with attenuated/atypical hemispheric asymmetry. An association may explain the co-occurrence of both dysfunctions in psychiatric populations. Methods. Healthy participants (n 129) performed a left hemisphere (lateralised lexical decision task) and right hemisphere (lateralised face decision task) dominant task as well as a visual cartoon task to assess theory of mind performance. Results. Linear regression analyses revealed inconsistent associations between theory of mind performance and functional hemisphere asymmetry: enhanced theory of mind performance was only associated with (1) faster right hemisphere language processing, and (2) reduced right hemisphere dominance for face processing (men only). Conclusions. The majority of non-significant findings suggest that theory of mind and functional hemispheric asymmetry are unrelated. Instead of ''overinterpreting'' the two significant results, discrepancies in the previous literature relating to the problem of the theory of mind concept, the variety of tasks, and the lack of normative data are discussed. We also suggest how future studies could explore a possible link between hemispheric asymmetry and theory of mind.

OnTheBus

El projecte OnTheBus pretén ser un sistema de guiatge gratuït, destinat per a la plataforma mòbil Android, útil com a eina d’ajuda pel desplaçament d’un punt d’origen a un punt de destí dins de la ciutat, utilitzant la xarxa de transport metropolità. Aquesta memòria s’enllaça amb 6 memòries més, dels meus companys amb els qui he realitzat el projecte OnTheBus. Per poder elaborar amb èxit l’aplicació OntheBus, cal donar importància al disseny i a la implementació de la interfície d’usuari. L’objectiu d’aquesta memòria és explicar com s’ha realitzat i dissenyat l’aplicació perquè sigui accessible per a tothom. Ja que pot tenir un rang molt ampli d’edats d’usuaris, la implementació de la interfície està basada en les directrius del Disseny Universal.

OnTheBus

El projecte OnTheBus pretén ser un sistema de guiatge gratuït, destinat per a la plataforma mòbil Android, útil com a eina d’ajuda pel desplaçament d’un punt d’origen a un punt de destí dins de la ciutat, utilitzant la xarxa de transport metropolità. Aquesta memòria s’enllaça amb 6 memòries més, dels meus companys amb els qui he realitzat el projecte OnTheBus. Per poder elaborar amb èxit l’aplicació OntheBus, cal donar importància al disseny i a la implementació de la interfície d’usuari. L’objectiu d’aquesta memòria és explicar com s’ha realitzat i dissenyat l’aplicació perquè sigui accessible per a tothom. Ja que pot tenir un rang molt ampli d’edats d’usuaris, la implementació de la interfície està basada en les directrius del Disseny Universal.

Foreign ant queens are accepted but produce fewer offspring.

Understanding social evolution requires us to understand the processes regulating the number of breeders within social groups and how they partition reproduction. Queens in polygynous (multiple queens per colony) ants often seek adoption in established colonies instead of founding a new colony independently. This mode of dispersal leads to potential conflicts, as kin selection theory predicts that resident workers should favour nestmate queens over foreign queens. Here we compared the survival of foreign and resident queens as well as their relative reproductive share. We used the ant Formica exsecta to construct colonies consisting of one queen with workers related to this resident queen and introduced a foreign queen. We found that the survival of foreign queens did not differ from that of resident queens over a period of 136 days. However, the genetic analyses revealed that resident queens produced a 1.5-fold higher number of offspring than introduced queens, and had an equal or higher share in 80% of the colonies. These data indicate that some discrimination can occur against dispersing individuals and that dispersal can thus have costs in terms of direct reproduction for dispersing queens.