27,497 research outputs found
Patterns in megabenthic assemblages on a seamount summit (Ormonde Peak, Gorringe Bank, Northeast Atlantic)
No full textGettysburg and Ormonde are two shallow peaks located on the Gorringe seamount about 200 and 240 km WSW off Cape St. Vincent (Portugal, NE Atlantic), within the Portuguese Economic Exclusive Zone. Despite the ecological importance of the biological assemblages on these peaks and the need to preserve seamounts as valuable habitats, no management plans have been yet implemented at this site, which only recently has been included in the list of Sites of Community Importance of Portugal. Video imagery collected using a ROV during the 2011 Oceana campaigns was used here to analyse qualitative and quantitative patterns of benthic assemblage composition at the summit of the seamount (between 30 and 230 m depth). The results suggest that Ormonde is a biologically important area made up of vulnerable marine ecosystem elements that change significantly with depth. These include: kelp beds, in the euphotic zone; encrusting coralline algal communities and solitary colonies or mixed associations of suspension‐feeders (scleractinians, gorgonians, antipatharians, encrusting demosponges and ascidians), at the lower limit of the euphotic zone; mixed coral gardens and erect sponges, in the disphotic zone; and dense sponge aggregations, on the upper slope. These results were further used to propose amendments to the European Nature Information System habitat classification as a tool to work towards resolving the seamounts management issue. The results also provide information on taxa and habitats with high ecological value and classified as threatened or vulnerable, which is essential for the implementation of the cornerstones of Europe's biodiversity conservation policy, namely the OSPAR Convention and the EU Habitats Directive
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
The long-wavelength view of GG Tau A: rocks in the ring world
No full textWe present the first detection of GG Tau A at centimetre wavelengths, made with the Arcminute Microkelvin Imager Large Array at a frequency of 16 GHz (λ = 1.8 cm). The source is detected at >6 σrms with an integrated flux density of S16GHz = 249 ± 45 µJy. We use these new centimetre-wave data, in conjunction with additional measurements compiled from the literature, to investigate the long-wavelength tail of the dust emission from this unusual protoplanetary system. We use an MCMC-based method to determine maximum likelihood parameters for a simple parametric spectral model and consider the opacity and mass of the dust contributing to the microwave emission. We derive a dust mass of Md ~ 0.1 Msun, constrain the dimensions of the emitting region and find that the opacity index at λ > 7 mm is less than unity, implying a contribution to the dust population from grains exceeding ~4 cm in size. We suggest that this indicates coagulation within the GG Tau A system has proceeded to the point where dust grains have grown to the size of small rocks with dimensions of a few centimetres. Considering the relatively young age of the GG Tau association in combination with the low derived disc mass, we suggest that this system may provide a useful test case for rapid core accretion planet formation models
Bounds for increasing multi-state linear <i>k</i>-within-(<i>r</i>,<i>s</i>)-of-(<i>m</i>,<i>n</i>):<i>F</i> lattice system
No full text
Purpose
A multi-state linear k-within-(r, s)-of-(m, n): F lattice system consists of m×n components arranged in m rows and n columns. The possible states of the system and its components are: 0, 1, 2, …, H. According to k values, the system can be categorized into three special cases: decreasing, increasing and constant. The system reliability of decreasing and constant cases exists. The purpose of this paper is to evaluate the system reliability in increasing case with i.i.d components, where there is no any algorithm for evaluating the system reliability in this case.
Design/methodology/approach
The Boole-Bonferroni bounds were applied for evaluating the reliability of many systems. In this paper, the author reformulated the second-order Boole-Bonferroni bounds to be suitable for the evaluation of the multi-state system reliability. And the author applied these bounds for deriving the lower bound and upper bound of increasing multi-state linear k-within-(r, s)-of-(m, n): F lattice system.
Findings
An illustrated example of the proposed bounds and many numerical examples are given. The author tested these examples and concluded the cases that make the new bounds are sharper.
Practical implications
In this paper, the author considered an important and complex system, the multi-state linear k-within-(r, s)-of-(m, n): F lattice system; it is a model for many applications, for example, telecommunication, radar detection, oil pipeline, mobile communications, inspection procedures and series of microwave towers systems.
Originality/value
This paper suggests a method for the computation of the bounds of increasing multi-state linear k-within-(r,s)-of-(m,n): F lattice system. Furthermore, the author concluded that the cases that make these bounds are sharper.
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Productive performance of 20 varieties of fodder nopal (Opuntia spp.) in the semi-arid Northeast, Brazil.
No full textDue to poor soils and high minimum temperature (above 20.5o C), the ‘Sertão’ region, located in the Brazilian Semi-arid Northeast, is probably one of the harshest cropping environments in the world, in which nopal i s grown for f odder production. Recently, another problem appeared, the armored scale insect (Diaspis echinocacti - Bouchè). A field trial with twenty varieties was started in April 2000 in Petrolina, Pernambuco, (average rainfall 552.2 mm, 80% available in December through April). The varieties tested were: three local cultivars, ‘Gigante’, the most cultivated, ‘Redonda’ (both Opuntia ficus-indica) and ‘Doce’ nopal (Nopalea cochenillifera) and Clone IPA- 20, eight varieties of highest performance in a preliminary evaluation2, that are identified by a number such as, 1258 - Additional Cv.; eight varieties provided by IPA, and identified by a number such as, IPA-90-73, and n ever tested in the region.. The e xperimental design was, a randomized complete block, with four replications, in p lots of 3.5 m2, made up o f one seven-plant li ne, for evaluation, on ly five plants/line were c onsidered. Planting density was 20.000 p lants/ha. Manure was applied on biannual basis at the rate of 2.86 kg/m.. Weeding was done with hoes. In May 2004, the first harvest was done, collecting all fresh material except t he basal pad and the first l ayer of pads. Annual fresh matter (FM) production was calculated d ividing total yield by four. Mean production was 75.24 ± 33.61 ton FM/ha/year (CV = 44.7 %). The eight most productive varieties, with FM production/ha/year, h eight and transversal canopy diameter in p arenthesis were: 1258 - Additional cv. (115.25 ton; 1.50 and 0.96 m); IPA-90-73 (106.75 ton; 1.53 and 1.16 m); Clone IPA-20 (101.12 ton; 1.46 and 1.09 m); 1278 - Mexico Fodder (99.00 ton; 1.68 and 0.88 m); IPA- 90-155 (96.75 ton; 1.50 and 1.05 m); IPA-90-75 (86.92 ton; 1.32 and 1.00 m); 1311 - Marmillon Fodder (85.55 ton; 1.64 and 0.78 m); 1267 - Algeria Fodder (85.25 ton; 1.18 and 1.18 m). ‘Gigante’ nopal (68.00 ton; 1.43 and 1.05 m) stayed in 13 o position, as in research cited b elow. There was no d ifference (P<0.05) among these treatments, du e to h igh CV. Other data, such as, protein and fiber levels, that are still under analysis, might indicate that highest production does not assure the best variety for the region. Shorter transversal canopy diameter such as in 1278 - Mex... and 1311 - Mar..., would make these varieties more suitable for intercropping with annual cro
Oxyepoecus myops Albuquerque & Brandão, 2009, n. sp.
No full textOxyepoecus myops n. sp. (Figs. 1a-c, 6) Oxyepoecus myops n. sp. Albuquerque & Brandão. Holotype: worker. Brazil: São Paulo: Salesópo- lis [23°39'S, 45°53'W], 05-07.vii.1997, C.I. Yamamoto col., extracted from the leaf litter using Winkler extractor; deposited in MZSP. Paratypes (all from Brazil): São Paulo: thirty workers and three gynes from Salesópolis (same locality of the Holotype, but collected in different dates and by different collectors), deposited in MZSP, one worker deposited in AMNH, one worker deposited in CASC, one worker deposited in CECL, one worker deposited in CPDC, one worker deposited in ICNC, one worker deposited in LACM, one worker deposited in MIZA, one worker deposited in USNM. Etymology: The specific name refers to the relatively minute size of the compound eyes that characterize workers of this species. Worker (Holotype and paratypes (N = 30), variation within brackets): t.l. = 2.08 (1.95-2,15); h.l. = 0.53 (0.50-0.53); h.w. = 0.40 (0.38-0.43); s.l. = 0.30 (0.28-0.31); m.l.e. = 0.06 (0.05-0.08); m.w.pr. = 0.25 (0.23-0.28); a.l. = 0.60 (0.58-0.60); h.f.l. = 0.33 (0.28-0.33); m.w.p. = 0.15 (0.13-0.18); m.w.pp. = 0.20 (0.18-0.20); c.i. 75 (76-81). Color chestnut brown, legs and antennae slightly lighter. Integument with irregularly reticulate sculpture covering almost all head dorsum, except close to clypeus, and around antennal insertions; almost all mesosoma, petiole dorsum and postpetiole with irregulary reticulate sculpture; gaster smooth and shining. Hairs relatively abundant, short, subdecumbent and curved mesad on head dorsum, and anteriorly curved on the head sides; long and suberect on dorsum of mesosoma, petiole and postpetiole; hairs on gaster decumbent and shorter. Mandible with basal border approximately equal chewing border, basal tooth separated from subbasal tooth by shallow diastema. Anterior tooth of clypeus with lateral, blunt denticle. Frontal carinae short, subparallel, with posterior end at level of anterior margin of compound eye, maximum width between their outer edges less than one fourth of head width. Compound eye very small, with 3-4 facets r.g.d.; total number of ommatidia not exceeding 7. Antennal scape fails to reach vertexal margin by distance greater than maximum scape width. Funnicular segment I longer than either VIII or IX, as long as II-V combined, segments II-VII distinctly broader than long, VIII and IX as long as broad. Head with vertexal margin straight (f.f.v.). Mesosoma with lateral and dorsal surfaces of pronotum not forming a well marked angle, slightly rounded. Metanotal groove weakly impressed (p.v.). Basal face of propodeum immarginate on sides, posteriorly with a small and obliquely directed tooth (p.v.). Declivous face laterally weakly carinate. Petiole pedunculate, node scarcely compressed antero-posteriorly (d.v.); subpetiolar process with an- terior end as a small and obliquely oriented denticle. Postpetiole strongly compressed antero-posteriorly, not as high as petiolar node; subpostpetiolar process shaped as small, transversal crest, parallel to ventrally produced posterior socket of postpetiole. Gyne (variation of three paratype gynes): t.l. = (2.53-2.58); h.l. = (0.55-0.56); h.w. = (0.45-0.48);s.l. = (0.33-0.35); m.l.e. = (0.20-0.25); m.w.pr. = (0.43-0.45); a.l. = (0.70-0.73); h.f.l. = (0.38-0.40); m.w.p. = (0.18-0.20); m.w.pp. = (0.28-0.30); c.i. (81-86). Characters almost the same as workers, with the differences of the caste: the three ocelli with same diameter, approximately equal to minimum scape width, compound eye with 10 facets r.g.d., about 30 in all, scutellum not marginate. Male: unknown. Examined material: BRAZIL: Minas Gerais, Conceicao do Mato Dentro, Serra da Serpentina, 18-28. iii.2009, Silva R.R. 067589/7894569 WGS 84 (1 [worker]); Paraná: Tunas, Parque das Lauráceas, 21-29. ii.2001, [R.R.] Silva and [F.] Eberhardt cols., transecto1 Winkler 16 [24°51'S, 48°43'W] (1 [worker]); Rio de Janeiro: Santa Maria Madalena, P[arque] E[stadual] do Desengano, x.2002, Mayhé, A. & Veiga-Ferreira, S. cols., # 48 and # 17 [21°58'S, 41°57'W] (2 [worker]); Nova Iguaçú, Re[serva] Bio[lógica] do Tinguá, ii.2002, Mayhé, A. & Veiga-Ferreira, S. cols., # 48 A10 [22°34'S, 43°24'W] (1 [worker]); Teresópolis, P[arque] N[acional] da S[erra] dos O[rgãos], 23-27.xi.1999, Rocha [R.P.], Dietz [B.H.], Silva [R.R.] cols., # 03 [22°27'S, 42°59'W] (1 [worker]); Santa Catarina: Blumenau, P[arque] E[stadual] das Nascentes, 20-27.x.2000, Silva, R.R. and Eberhardt, F. cols., [27°06'S, 49°09'W] (1 S); São Bonifácio, P[arque] E[stadual] Serra do Tabuleiro, 08-13.iii.2004, Silva, R.R.; Dietz, B.H. and Albuquerque, N.L. cols., [27°49'S, 48°54'W] (7 S, 1 T); Seara, v-xii.1998, Rogério R. Silva col. 24°07'S, 52°18'W (1 S); same locality, vi-vii.1999, same collector(7 S); São Paulo: Botucatu, 07.x.1987, Forti, L.C. and Rinaldi, I.M.P. cols [22°53'S, 48°26'W] (5 S - soil trap collected); Campos do Jordão, xi.1985, C.G. Froelich col. [22°44'S, 45°34'W] (2 S); Juquitiba, 30.x.1960, W.W. Kempf col. [23°56'S, 47°02'W] (1 S); São Paulo, P[arque] E[stadual] da Cantareira - Núcleo Engordador, 12-22.v.2003, R. Feitosa & A. Soliva cols. 23°21'S, 46°29'W (2 S); Salesópolis, 03-05.v.1996, Brandão [,C.R.F]; Agosti [,D.]; Diniz[,J.]; Silvestre, [,R.]; Yamamoto [,C.I.] [cols.] [23°39'S, 45°53'W] (4 S and 2 T); same locality, 02-06.v.1997, D. Agosti; C.R.F. Brandão; & C.I. Yamamoto cols (15 S); same locality, 05-07.vii.1997, C.I. Yamamoto col. (5 S); same locality, 05-07. ix.1997, C.I.Yamamoto, col. (4 S); Tapiraí, 08-14. i.2001, Silva, R.R. and Eberhardt, F. cols., [24°01'S, 47°27'W] (1 S) Cunha, P[arque] E[stadual] Serra do Mar (23°15'03"S, 45°00'26"W), 21-22.iv.2001, A. Tavares & R.R. Silva (samples # 5, 15, 28, 36, 38, 48, 50).(3 T and 8 S). Comments: The exclusive character of Oxyepoecus myops n. sp. workers in relation to the other species of the Rastratus group is the irregularly reticulate sculpture fully covering the head dorsum and almost all the mesosoma dorsum. Their compound eyes are the smallest in the genus. The distribution of O. myops n. sp. includes several Southern Brazil localities, and in Minas Gerais, São Paulo and Rio de Janeiro States. Workers of this species have been recently extracted from litter samples taken in localities at sea level and up to more than 1000 m high in the Serra do Mar Range. Most localities are covered by dense evergreen tropical forests, but in some cases, samples come from drier forests as well, as in Seara, SC and Teresópolis, RJ. In Serra da Cantareira, S P, workers were attracted to sardine baits set on the forest floor during the day.Published as part of Albuquerque, N. L. de & Brandão, C. R. F., 2009, A revision of the Neotropical Solenopsidini ant genus Oxyepoecus Santschi, 1926 (Hymenoptera: Formicidae: Myrmicinae). 2. Final. Key for species and revision of the rastratus species-group., pp. 289-309 in Papeis Avulsos do Departamento de Zoologia 49 on pages 295-29
Triple F-a comet nucleus sample return mission
No full textThe Triple F (Fresh From the Fridge) mission, a Comet Nucleus Sample Return, has been proposed to ESA's Cosmic Vision program. A sample return from a comet enables us to reach the ultimate goal of cometary research. Since comets are the least processed bodies in the solar system, the proposal goes far beyond cometary science topics (like the explanation of cometary activity) and delivers invaluable information about the formation of the solar system and the interstellar molecular cloud from which it formed. The proposed mission would extract three sample cores of the upper 50cm from three locations on a cometary nucleus and return them cooled to Earth for analysis in the laboratory. The simple mission concept with a touch-and-go sampling by a single spacecraft was proposed as an M-class mission in collaboration with the Russian space agency ROSCOSMOS. © The Author(s) 2008
Desenvolvimento e caracterização de argilas organofílicas para uso em alimentação animal como adsorvente inativador de micotoxinas: aflatoxina B1 e fumonisina B1
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Química.As argilas são utilizadas como matéria-prima para diversas aplicações na indústria. Nestes processos industriais as argilas mais procuradas são as bentonitas. As bentonitas são argilas amplamente encontradas na natureza e possuem propriedades tecnológicas bastante atraentes para o desenvolvimento de produtos para as mais variadas áreas. As propriedades tecnológicas que mais despertam o interesse industrial são: (a) capacidade de troca de cátions, (b) grau de inchamento, e (c) alto poder de adsorção. Estas propriedades podem ser modificadas através de tratamentos térmicos e também por tratamentos químicos. Os métodos de obtenção de argilas organofílicas têm sido estudados extensivamente. As argilas organofílicas são argilas quimicamente modificadas sendo o agente transformador a espécie química de amina quaternária. O processo para obtenção de argilas organofílicas consiste na preparação de uma solução de sal quaternário de amônio que contém os cátions orgânicos. Esta solução é adicionada à suspensão de bentonita proporcionando assim a troca dos cátions trocáveis inorgânicos da bentonita pelos cátions trocáveis orgânicos da solução de sal quaternário. O Brasil possui depósitos de bentonitas policatiônicas na região nordeste nos estados da Paraíba, Piauí, Pernambuco e Bahia. Também na região sudeste nos estados de São Paulo e Minas Gerais. Na Região Sul no estado do Paraná também foram observadas jazidas de bentonita. A produção interna bruta de bentonita ainda é modesta. Em 2002 as reservas brasileiras de bentonita totalizaram 78 milhões de toneladas das quais 46,1% são relativos às reservas medidas. A produção nacional de bentonita bruta obteve um aumento expressivo de 62% e a beneficiada um acréscimo mais modesto de 9,1% por isso a exportação da bentonita brasileira é ainda pouco significativa. O Brasil continua importando cerca de 27% dessa matéria-prima principalmente de países da América latina como Argentina, de onde são importados 48% destes bens primários. Neste trabalho de tese três tipos de bentonitas de formações distintas foram usadas como matéria-prima para a obtenção de organofílicas. Uma bentonita nacional do estado do Paraná, município de Quatro Barras e duas outras importadas da Argentina. As bentonitas da Argentina são da província de Neuquén (região centro-oeste), e da província de San Juan (região oeste). O agente transformador utilizado foi um sal quaternário de amônio importado e comercializado pela Fluka, denominado cloreto de alquil benzil dimetil amônio ou cloreto de benzalcônio. O objetivo da pesquisa é estudar o grau de adsorção das bentonitas organofílicas desenvolvidas com relação às micotoxinas. Micotoxinas são poluentes orgânicos encontrados em grãos e rações administradas aos animais. Existem pelo menos 200 tipos de micotoxinas catalogadas. Dentre estas, 14 são carcinogênicas. Nesta tese dois tipos de micotoxinas chamadas Aflatoxina B1 e Fumonisina B1 foram estudadas. Elas são as de maior ocorrência no Brasil e em países da América latina. A etapa inicial do trabalho de tese foi realizar um estudo químico e mineralógico nas bentonitas naturais usando técnicas e métodos como análise química, difração de Raiox X, análises térmicas, densidade real, porosidade, microscopia eletrônica de varredura, espectroscopia na região do infravermelho e cromatografia líquida de alta eficienciência. A segunda etapa foi realizar a transformação organofílica utilizando o sal quaternário cloreto de benzalcônio. Na terceira etapa, um estudo químico e mineralógico foi realizado com o objetivo de verificar as transformações efetivadas com o processamento organofílico nas três bentonitas organofílicas desenvolvidas. E o teste de adsorção in vitru foi realizado nas amostras organofílicas. Os resultados mostram que as três bentonitas organofílicas desenvolvidas conseguem adsorver melhor as aflatoxinas B1 e fumonisinas B1 que antes do tratamento com o sal quaternário de amônio. Numa comparação entre as três bentonitas estudadas os melhores níveis de adsorção para as micotoxinas estudadas foram observados para a bentonita de Neuquén. Clays are used as row material for different applications in industrial processes. In addition, bentonites are mainly searched to use in these Bentonites are a kind of clay widely found in nature and they have technological properties being suitable for the development of products used in several areas. The main technological properties are: (a) cation exchange capacity, (b) swelling degree, and (c) high adsorption. These properties can be modified by way of thermal treatments and also by chemical ones. Methods to obtein organophilic clays have been studied deeply. Organophilic clays are obteined by modifying natural clays with chemical processes by using the quaternary amine. The obtention process of organophilic clays is made up of the preparation of a solution of ammonium quaternary salt which has organics cations. This solution is added to a bentonite suspention given, in this way, the interchange between inorganic interchanging cations of the bentonite and the organic ones of the solution of salt. Brazil has deposits of policationic bentonites in the northeast region in the states of Paraíba, Piauí, pernambuco and Bahia. In the southeast region in the states of São Paulo and Minas Gerais, too. In the south region, more precisely, in the states of Paraná deposits of bentonite were observed. However, the internal production is still modest. In 2002 the Brazilian reserves of bentonites were 78 millions of tons which 46,1% were relative to measured reserves. The national production of row bentonite has shown an important increase of 62%. An the other hand, the production of improved bentonites has had a modest increment of 9,1%. For this reason, the explotation of Brazilian bentonites is not very significant. Brazil imports almost 27% of this kind of clay, mainly of coutries of latin American as Argentina. In this Thesis, three kinds of bentonites were used as row material to obtain organophilic clays. One national bentonite from Paraná, Quatro Barras and two imported from Argentina. The Argentinian bentonites were from Neuqén province (West Center Region) and San Juan province (West Region). A imported ammonium quaternary salt which is called as dimethil benzil alquil ammonium chloride or benzalkonium chloride was used as transforming agent. The objective of this research is to study the degree of adsorption of the developed organophilic clays when they are used to adsorb mycotoxins. Mycotoxins are organic pollutes found in animal feed as for example corn grains. There are aproximately 200 sorts of identified mycotoxins. Among them, 14 are cancerogenic. The latter set, two mycotoxins were studied, namely Aflatoxin B1 and Fumonisin B1 since they appears frequently in Brazil and the rest of countries of latin America. First at all, the chemical and mineralogic study of the natural bentonites were performed by using methods and techniques as chemical analysis, X ray diffraction, thermal analysis, real density porosity, scanned electronic microseopy, infrared spectroscopy and high efficiency liquid chromatography. After that, the transformation in organophilic clay by using the benzalkonium chloride salt took place. Finaly, a chemical and mineralogic study was corried out in order to verify the organic transformations into the three developed organophilic bentonites. The in vitru adsorption test was made with the organophilic samples. Its results showed that the three organophilic bentonites adsorb Aflatoxins B1 and Fumonisins B1, being their adsorption degrees larger than the respective ones for the natural bentonites. By comparing these results, it is possible to see that the better result was obtained for the bentonite of Neuquén
Ordre de naixement i risc per al trastorn per dèficit d'atenció amb o sense hiperactivitat
No full textEl nostre estudi aporta dades no descrites amb anterioritat sobre la possible influència de l’ordre de naixement en el desenvolupament del TDAH.
L’estudi es va realitzar en dues etapes. Un primer estudi, preliminar, va avaluar en una mostra clínica ambulatòria amb diagnòstic TDAH la freqüència de primogènits respecte a d’altres ordres de naixement. Es va trobar un predomini de primogènits a la mostra. En un segon estudi es va analitzar el risc de tenir TDAH segons l’ordre de naixement, trobant-se un risc incrementat del primogènit de quasi el doble de patir TDAH respecte a d’altres ordres.
Els estudis han generat les següents publicacions:
Masana Marin, A., Lopez Seco, F., Marti Serrano, S., & Acosta Garcia, S. (2011). Correspondence on ''attention-deficit hyperactivity disorder (ADHD) and birth order''. Journal of Child Neurology, 26(3), 395; author reply 395-6.
Marin, A. M., Seco, F. L., Serrano, S. M., Garcia, S. A., Gaviria Gomez, A. M., & Ney, I. (2012). Do firstborn children have an increased risk of ADHD? Journal of Attention Disorders, 23 jul. 2012. DOI: 10.1177/1087054712445066 .Our study provides data not previously described on the possible influence of birth order on the development of ADHD .
The study was conducted in two stages. The first study , preliminary evaluated in a patient diagnosed with ADHD clinical sample frequency firstborn over other birth orders . We found a predominance of the firstborn in the sample. In a second study analyzed the risk of ADHD in order of birth , being the eldest son of an increased risk of suffering from ADHD almost double compared to other orders.
Studies have produced the following publications :
Masana Marin , A. , Seco Lopez , F. Martin Serrano, S. , & Acosta Garcia , S. (2011 .) Correspondence on '' attention deficit hyperactivity disorder , ( ADHD ) and birth order .'' Journal of Child Neurology , 26 (3), 395 , author reply 395-6 .
Marin , A. M. Seco , F. L. Serrano, S. M. Garcia , S. A. Gomez Gaviria , A. M. , & Ney , E. (2012 .) Do Firstborn children have an increased risk of ADHD ? Journal of Attention Disorders, 23 July , 2012. DOI : 10.1177/1087054712445066
Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis
No full textMultiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis
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