Estudos anatômicos e histológicos sôbre a sub-família Triatominae (Heteropterareduviidae): parte XVIII: sistema traqueal do Triatoma infestans

O presente trabalho consta de um estudo sõbre a topografia do sistema traqueal em Triatoma infestans. Com esta finalidade empregaram-se diversas técnicas de coloração por infiltração, além de introduzir-se uma modificação no método de Gäbler. Foram usados vários fixadores e feitas muitas Lâminas histológicas para a comprovação dos resultados. É apresentado, na parte referente a considerações gerais sôbre o sistema, uma citação de alguns autores que mais se dedicaram ao estudo do aparelho respiratório nos insetos. O estudo sôbre a distribuição do sistema traqueal abrange ambos os sexos, porém, é limitado a exemplares adultos. O assunto é abordado em 3 seções: 1) traquéias da região cefálica; 2) traquéias da região torácica; e 3) traquéias da região abdominal. O percurso das traquéias da região cefálica é acompanhado e estudado em todo o trajeto, o mesmo acontecendo com as do tórax e do abdômen. A disposição do sistema em estudo, na região torácica, apresenta-se bem amis complexa e com inúmeras ramificações, que se destinam aos diversos órgãos desta região. É estudada, também, a distribuição dos ramos traqueais nas pernas e nas asas do inseto. É evidenciado um rompimento na continuidade do sistema traqueal, na altura do 1º para o 2º estígmas abdominais. Supõe-se que êste fato esteja ligado ao desaparecimento do 1º esternito e a migração do esclerito contendo o 1º estígma abdominal, para a região dorsal do inseto. Devido a êste fenômeno, o sistema traqueal do Triatoma infestans apresenta-se diferente, funcionando como se fôsse dos sistemas independentes entre si. As diferenças, o número e a disposição das traquéias na região abdominal é abordado amplamente, assim como, realçada a formação e função dos citados sacos traqueais.

Estudos anatômicos e histológicos sôbre a sub-família Triatominae (Heteroptera, Reduviidae): Parte XX: estudo comparado dos estigmas nas espécies mais importantes

É feito um estudo comparado sôbre a estrutura e o mecanismo dos estigmas de Triatoma vitticeps, Triatoma maculata, Triatoma sórdida, Triatoma brasiliensis, Rhodnius prolines e Panstrongyius megistus com os de Triatoma infestans, anteriormente já tratados. É, assim, elaborada uma tabela comparativa sôbre o tamanho e localização, dos espiráculos torácicos e abdominais, nas espécies citadas. Os estigmas mesotorácicos nas espécies do gênero Triatoma apresentam-se com várias modificações morfológicas, porém, não tão significantes como as encontradas em Panstrongyius megistus e Rhodnius prolixus. Seu mecanismo mostra acentuadas diferenças morfológicas. De um modo geral, os estigmas mesotorácicos possuem uma zona dorsal e outra ventral, que se diferenciam nas diferentes espécies e gêneros. A abertura do átrio para o exterior faz-se, perpendicularmente ao eixo maior do corpo do inseto. Nota-se uma região onde a cutícula é mais espêssa e que serve de base para a implantação dos músculos destinados ao seu funcionamento. O côndilo, que varia quanto à forma, nos diversos Triatomíneos, não é evidenciado nos estigmas metatorácicos. Os espiráculos metatorácicos encontram-se ocultos, totalmente, pelos escleritos do mesotórax e metatórax. O aspecto morfológico do mesmo é semelhante ao do mesotorácico, porém, apresenta algumas diferenças. Os espiraculos abdominais são em número de 8 pares. O 1.º par está situado na região látero-dorsal da membrana intersegmental, entre o tórax e o abdômen. Em Rhodnius prolixus o estigma apresenta-se circundado por zonas esclerosadas, em forma de listas. Nos demais Triatomíneos os escleritos estigmatíferos são semelhantes e menos reforçados. A forma e a estrutura e o mecanismo dêstes estigmas variam em todas as espécies citadas, Encontram-se 3 elementos de proteção à traquéia que se limita com o átrio. São eles: 1) rêde protetora que recobre parcialmente a entrada do estigma, semelhante a um peritrema; 2) côndilo interno que comanda a entrada e saída do ar das traquéias; e 3) falsos espinhos, situados no átrio e que variam de tamanho e espessura nos diferentes Triatomíneos. Finalmente, observa-se o VIII par de estigmas abdominais, cuja forma, mecanismo e localização o diferenciam dos demais. Êste par encontra-se citado por alguns autores, porém, na realidade, sua estrutura só é apresentada no presente trabalho.

Convergence of the mass-transport steepest descent scheme for the sub-critical Patlak-Keller-Segel model

Variational steepest descent approximation schemes for the modified Patlak-Keller-Segel equation with a logarithmic interaction kernel in any dimension are considered. We prove the convergence of the suitably interpolated in time implicit Euler scheme, defined in terms of the Euclidean Wasserstein distance, associated to this equation for sub-critical masses. As a consequence, we recover the recent result about the global in time existence of weak-solutions to the modified Patlak-Keller-Segel equation for the logarithmic interaction kernel in any dimension in the sub-critical case. Moreover, we show how this method performs numerically in one dimension. In this particular case, this numerical scheme corresponds to a standard implicit Euler method for the pseudo-inverse of the cumulative distribution function. We demonstrate its capabilities to reproduce easily without the need of mesh-refinement the blow-up of solutions for super-critical masses.

A relative double commutant theorem for hereditary sub-C*-algebras

We prove a double commutant theorem for hereditary subalgebras of a large class of C*-algebras, partially resolving a problem posed by Pedersen[8]. Double commutant theorems originated with von Neumann, whose seminal result evolved into an entire field now called von Neumann algebra theory. Voiculescu proved a C*-algebraic double commutant theorem for separable subalgebras of the Calkin algebra. We prove a similar result for hereditary subalgebras which holds for arbitrary corona C*-algebras. (It is not clear how generally Voiculescu's double commutant theorem holds.)

Transcatheter stent-valve implantation in a stenotic pulmonary conduit via a sub-xyphoidian access

Patients who develop a severe stenosis in biological pulmonary conduits previously implanted for pulmonary outflow trunk reconstructions are treated either by surgical re-replacement, or by transcatheter stent-valve implantation through a femoral vein access. A catheter-based sub-xyphoidian access through the right ventricle for stent-valve positioning in a pulmonary conduit has rarely been proposed. We describe the case of a 20-year-old man who underwent a pulmonary trunk reconstruction for a congenital pulmonary valve dysplasia and a few years later developed a stenosis in the pulmonary conduit. He was successfully treated with a 23 mm Edwards Sapien stent-valve implantation in pulmonary position, through an unusual right ventricular, sub-xyphoidian access and without contrast medium injections and pleura opening.

Public Governance, Health and Foreign Direct Investment in Sub-Saharan Africa

In this paper we diverge from the existing empirical literature on FDI determinants in two ways. First, we decompose the sources of the foreign direct investment (FDI) gap between Sub-Saharan Africa (SSA) and other developing regions. Once market size has been accounted for, we nd that SSA's FDI de cit is mostly explained by insufficient provision of public goods: low human capital accumulation, especially health, in SSA explains 100-140% of the inter-regional FDI gaps. Second, we estimate the indirect effect of infectious diseases on FDI through their direct impact on health. We find that a 1% point rise in HIV prevalence in the adult population is associated with a decrease in net FDI inflows of 3.5%, while a country in which 100% of the population is at risk of contracting deadly malaria receives about 16% less FDI than a similar country located in a malaria-free region.

An ATP-binding cassette subfamily G full transporter is essential for the retention of leaf water in both wild barley and rice.

Land plants have developed a cuticle preventing uncontrolled water loss. Here we report that an ATP-binding cassette (ABC) subfamily G (ABCG) full transporter is required for leaf water conservation in both wild barley and rice. A spontaneous mutation, eibi1.b, in wild barley has a low capacity to retain leaf water, a phenotype associated with reduced cutin deposition and a thin cuticle. Map-based cloning revealed that Eibi1 encodes an HvABCG31 full transporter. The gene was highly expressed in the elongation zone of a growing leaf (the site of cutin synthesis), and its gene product also was localized in developing, but not in mature tissue. A de novo wild barley mutant named "eibi1.c," along with two transposon insertion lines of rice mutated in the ortholog of HvABCG31 also were unable to restrict water loss from detached leaves. HvABCG31 is hypothesized to function as a transporter involved in cutin formation. Homologs of HvABCG31 were found in green algae, moss, and lycopods, indicating that this full transporter is highly conserved in the evolution of land plants.

Native-like, long synthetic peptides as components of sub-unit vaccines: practical and theoretical considerations for their use in humans.

Vaccines have been used as a successful tool in medicine by way of controlling many major diseases. In spite of this, vaccines today represent only a handful of all infectious diseases. Therefore, there is a pressing demand for improvements of existing vaccines with particular reference to higher efficacy and undisputed safety profiles. To this effect, as an alternative to available vaccine technologies, there has been a drive to develop vaccine candidate polypeptides by chemical synthesis. In our laboratory, we have recently developed a technology to manufacture long synthetic peptides of up to 130 residues, which are correctly folded and biologically active. This paper discusses the advantages of the molecularly defined, long synthetic peptide approach in the context of vaccine design, development and use in human vaccination.

Glomus intraradices induces changes in root system architecture of rice independently of common symbiosis signaling

? Arbuscular mycorrhizal fungi colonize the roots of most monocotyledons and dicotyledons despite their different root architecture and cell patterning. Among the cereal hosts of arbuscular mycorrhizal fungi, Oryza sativa (rice) possesses a peculiar root system composed of three different types of roots: crown roots; large lateral roots; and fine lateral roots. Characteristic is the constitutive formation of aerenchyma in crown roots and large lateral roots and the absence of cortex from fine lateral roots. Here, we assessed the distribution of colonization by Glomus intraradices within this root system and determined its effect on root system architecture. ? Large lateral roots are preferentially colonized, and fine lateral roots are immune to arbuscular mycorrhizal colonization. Fungal preference for large lateral roots also occurred in sym mutants that block colonization of the root beyond rhizodermal penetration. ? Initiation of large lateral roots is significantly induced by G. intraradices colonization and does not require a functional common symbiosis signaling pathway from which some components are known to be needed for symbiosis-mediated lateral root induction in Medicago truncatula. ? Our results suggest variation of symbiotic properties among the different rice root-types and induction of the preferred tissue by arbuscular mycorrhizal fungi. Furthermore, signaling for arbuscular mycorrhizal-elicited alterations of the root system differs between rice and M. truncatula.

La crisi sub-prime i el crack de 1929: Comparació d'episodis d'eufòria financera

Treball de recerca realitzat per un alumne d'ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit científic del Jovent l'any 2009. La present investigació té per objecte d’estudi la relació, atès el període de turbulències econòmiques que travessa el món globalitzat, entre els episodis d’eufòria financera i les crisi financeres i econòmiques, i la periodicitat amb les que aquestes es produeixen. Aquesta pretén confrontar-se des d’una aproximació històric-econòmica, mitjançant l’anàlisi i la comparació de dos successos -el crack borsari de 1929 i la crisi sub-prime- per tal de demostrar la existència de comuns denominadors, i, a la llum dels resultats, apreciar les conclusions que aporta la Història. Serà, doncs, aquesta periodicitat i les seves implicacions la qual s'ambicionarà contrastar amb la realitat mitjançant l'aplicació i l'anàlisi pràctica de dos episodis rellevants i paradigmàtics, amb el recolzament i l'autoritat del model comparatiu establerts per l'economista John Kenneth Galbraith al seu llibre ''Breve historia de la euforia financiera''.

Suicidal expression among school-attending adolescents in a middle-income sub-Saharan country.

We investigated correlates for suicidal expression among adolescents in the Seychelles. Data on 1,432 students (52% females) were derived from the Global School-based Health Survey. Participants were divided into three groups: those with no suicidal behavior (N = 1,199); those with suicide ideation/SI (N = 89); and those reporting SI with a plan to carry out a suicide attempt/SISP (N = 139), each within a 12-month recall period. Using multinomial logistic regression, we examined the strength of associations with social, behavioral and economic indicators while adjusting for covariates. Sixteen percent of school-attending adolescents reported a suicidal expression (10% with a plan/6.2% without). Those reporting SI were younger (relative risk ratio RRR = 0.81; CI = 0.68-0.96), indicated signs of depression (RRR = 1.69; CI = 1.05-2.72) and loneliness (RRR=3.36; CI =1.93-5.84). Tobacco use (RRR = 2.34; CI = 1.32-4.12) and not having close friends (RRR = 3.32; CI = 1.54-7.15) were significantly associated with SI. Those with SISP were more likely to be female (RRR = 0.47; 0.30-0.74), anxious (RRR = 3.04; CI = 1.89-4.88) and lonely (RRR = 1.74; CI = 1.07-2.84). Having no close friends (RRR = 2.98; 1.56-5.69) and using tobacco (RRR = 2.41; 1.48-3.91) were also strongly associated. Having parents who were understanding was protective (RRR = 0.50; CI = 0.31-0.82). Our results suggest that school health promotion programs may benefit from targeting multiple factors associated with suicidal expression. More research, particularly multilevel designs are needed to identify peer and family influences which may modify associations with suicidality.

Sub-cortical and brainstem sites associated with chemo-stimulated increases in ventilation in humans.

We investigated the neural basis for spontaneous chemo-stimulated increases in ventilation in awake, healthy humans. Blood oxygen level dependent (BOLD) functional MRI was performed in nine healthy subjects using T2 weighted echo planar imaging. Brain volumes (52 transverse slices, cortex to high spinal cord) were acquired every 3.9 s. The 30 min paradigm consisted of six, 5-min cycles, each cycle comprising 45 s of hypoxic-isocapnia, 45 s of isooxic-hypercapnia and 45 s of hypoxic-hypercapnia, with 55 s of non-stimulatory hyperoxic-isocapnia (control) separating each stimulus period. Ventilation was significantly (p<0.001) increased during hypoxic-isocapnia, isooxic-hypercapnia and hypoxic-hypercapnia (17.0, 13.8, 24.9 L/min respectively) vs. control (8.4 L/min) and was associated with significant (p<0.05, corrected for multiple comparisons) signal increases within a bilateral network that included the basal ganglia, thalamus, red nucleus, cerebellum, parietal cortex, cingulate and superior mid pons. The neuroanatomical structures identified provide evidence for the spontaneous control of breathing to be mediated by higher brain centres, as well as respiratory nuclei in the brainstem.

Segregation in a mycorrhizal fungus alters rice growth and symbiosis-specific gene transcription

Arbuscular mycorrhizal fungi (AMF) form symbioses with the majority of plants, improving plant nutrition and diversity. Evidence exists suggesting that AMF contain populations of genetically different nucleotypes coexisting in a common cytoplasm. This potentially has two important consequences for their genetics. First, by random distribution of nuclei at spore formation, new offspring of an AMF could receive different complements of nucleotypes compared to the parent or siblings-we consider this as segregation. Second, genetic exchange between AMF would allow the mixing of nuclei, altering nucleotype diversity in new spores. Because segregation was assumed not to occur and genetic exchange has only recently been demonstrated, no attempts have been made to test whether this affects the symbiosis with plants. Here, we show that segregation occurs in the AMF Glomus intraradices and can enhance the growth of rice up to five times, even though neither parental nor crossed AMF lines induced a positive growth response. This process also resulted in an alteration of symbiosis-specific gene transcription in rice. Our results demonstrate that manipulation of AMF genetics has important consequences for the symbiotic effects on plants and could be used to enhance the growth of globally important crops.