Searching singlet extensions of the supersymmetric standard model in Z6−II Z_{6-II} orbifold compactification of heterotic string

We search for supersymmetric standard model realizations with extra singlets and extra $U(1)$ using the heterotic string compactification on the $Z_{6-II}$ orbifold with two Wilson lines. We analyze the vacuum restabilization mechanism for three representative Pati-Salam string models obtained in the literature and present detailed results for the effective superpotential compatible with the string selection rules. An automated selection of semi-realistic vacua along flat directions in the non-Abelian singlet modes field space is performed by requiring the presence of massless pairs of electroweak Higgs bosons having trilinear superpotential couplings with massless singlet modes and the decoupling of color triplet exotic modes needed to suppress $B$ and $L$ number violating processes.Comment: revtex4 format, 21 pages, 7 tables, shortened version added reference

Gauge Unification in Supersymmetric Intersecting Brane Worlds

We show that contrary to first expectations realistic three generation supersymmetric intersecting brane world models give rise to phenomenologically interesting predictions about gauge coupling unification. Assuming the most economical way of realizing the matter content of the MSSM via intersecting branes we obtain a model independent relation among the three gauge coupling constants at the string scale. In order to correctly reproduce the experimentally known values of sin^2[theta_W(M_z)] and alpha_s(M_z) this relation leads to natural gauge coupling unification at a string scale close to the standard GUT scale 2 x 10^16 GeV. Additional vector-like matter can push the unification scale up to the Planck scale.Comment: 18 pages, harvmac & 3 figures; v2: one ref. adde

Gauge Coupling Unification and the Top Mass in String Models with SU(4)×O(4)SU(4)\times O(4) Symmetry

We discuss the low energy implications of gauge coupling unification at the string scale, taking into account string threshold corrections in the $SU(4) {\times} O(4)$ model. We express $sin^2\theta_W$ and $a_3$ as functions of the calculable string threshold differences and discuss simple examples of spectra which retain the successful predictions of the supersymmetric unification. Using further the low energy data and reasonable values of the common gauge coupling at the string scale, we obtain the range of the threshold corrections. Finally, we study the top Yukawa coupling ($h_t$) evolution whose initial value is determined in terms of the common gauge coupling at the string scale. We find that $h_t$ reaches its (quasi) infra-red fixed point at the weak scale and discuss the implications on the top mass.Comment: 12 pages, Plain Latex file, macros included in the beginning of the file, 3 figs on request from the authors. some minor typos are corrected, uu-encoded figures are included in a separate fil

Cell biological analysis reveals an essential role for Pfcerli2 in erythrocyte invasion by malaria parasites

Merozoite invasion of host red blood cells (RBCs) is essential for survival of the human malaria parasite Plasmodium falciparum. Proteins involved with RBC binding and invasion are secreted from dual-club shaped organelles at the apical tip of the merozoite called the rhoptries. Here we characterise P. falciparum Cytosolically Exposed Rhoptry Leaflet Interacting protein 2 (PfCERLI2), as a rhoptry bulb protein that is essential for merozoite invasion. Phylogenetic analyses show that cerli2 arose through an ancestral gene duplication of cerli1. We show that PfCERLI2 is essential for blood-stage growth and localises to the cytosolic face of the rhoptry bulb. Inducible knockdown of PfCERLI2 led to a proportion of merozoites failing to invade and was associated with elongation of the rhoptry organelle during merozoite development and inhibition of rhoptry antigen processing. These findings identify PfCERLI2 as a protein that has key roles in rhoptry biology during merozoite invasion.Benjamin Liffner, Juan Miguel Balbin, Gerald J. Shami, Ghizal Siddiqui, Jan Strauss, Sonja Frölich, Gary K. Heinemann, Ella May Edwards, Arne Alder, Jan Stephan Wichers, Darren J. Creek, Leann Tilley, Matthew W.A. Dixon, Tim-Wolf Gilberger, Danny W. Wilso

Tabelas de esperança de vida e fertilidade de Myzus persicae sobre pimentão em laboratório e casa de vegetação

Estudos de tabelas de vida de insetos-praga em diferentes temperaturas auxiliam na compreensão da dinâmica populacional desses organismos. Objetivou-se calcular tabelas de esperança de vida e de fertilidade de Myzus persicae criado em pimentão Capsicum annuum, em diferentes condições térmicas. O estudo foi realizado em câmaras climatizadas, nas temperaturas de 15, 20, 25 e 30 ºC, UR de 70±10% e fotofase de 12 horas, e em casa de vegetação em temperaturas oscilantes, com média de 24,9 ºC e UR de 68,1%. A longevidade máxima de adultos de M. persicae foi maior a 15 ºC (45 dias) e diminuiu a 20 ºC (39 dias), 25 ºC (27 dias), 30 ºC (24 dias) e, em casa de vegetação a 24,9 ºC foi de 29,5 dias. A esperança de vida (ex) no primeiro dia de observação foi de 43,76; 35,39; 21,44; 17,67 e 17,03 dias, para as ninfas mantidas a 15, 20, 25, 30 e 24,9 ºC respectivamente, tendo a partir daí uma queda acentuada até o fim das observações. Os parâmetros de tabelas de vida e de fertilidade evidenciaram que a temperatura de 25 ºC proporcionou a melhor condição térmica para o crescimento populacional de M. persicae, com maior capacidade de aumentar em número (r m = 0,31) e menor tempo necessário para a população duplicar (TD=2,22 dias). Em casa de vegetação a oscilação térmica afetou o crescimento populacional, proporcionando menor valor de r m (0,28) e maior TD (2,47 dias), comparados àqueles mantidos à temperatura constante equivalente

A class-wide phylogenetic assessment of Dothideomycetes

We present a comprehensive phylogeny derived from 5 genes, nucSSU, nucLSU rDNA, TEF1, RPB1 and RPB2, for 356 isolates and 41 families (six newly described in this volume) in Dothideomycetes. All currently accepted orders in the class are represented for the first time in addition to numerous previously unplaced lineages. Subclass Pleosporomycetidae is expanded to include the aquatic order Jahnulales. An ancestral reconstruction of basic nutritional modes supports numerous transitions from saprobic life histories to plant associated and lichenised modes and a transition from terrestrial to aquatic habitats are confirmed. Finally, a genomic comparison of 6 dothideomycete genomes with other fungi finds a high level of unique protein associated with the class, supporting its delineation as a separate taxon

A class-wide phylogenetic assessment of Dothideomycetes

We present a comprehensive phylogeny derived from 5 genes, nucSSU, nucLSU rDNA, TEF1, RPB1 and RPB2, for 356 isolates and 41 families (six newly described in this volume) in Dothideomycetes. All currently accepted orders in the class are represented for the first time in addition to numerous previously unplaced lineages. Subclass Pleosporomycetidae is expanded to include the aquatic order Jahnulales. An ancestral reconstruction of basic nutritional modes supports numerous transitions from saprobic life histories to plant associated and lichenised modes and a transition from terrestrial to aquatic habitats are confirmed. Finally, a genomic comparison of 6 dothideomycete genomes with other fungi finds a high level of unique protein associated with the class, supporting its delineation as a separate taxon

Size Doesn't Matter: Towards a More Inclusive Philosophy of Biology

notes: As the primary author, O’Malley drafted the paper, and gathered and analysed data (scientific papers and talks). Conceptual analysis was conducted by both authors.publication-status: Publishedtypes: ArticlePhilosophers of biology, along with everyone else, generally perceive life to fall into two broad categories, the microbes and macrobes, and then pay most of their attention to the latter. ‘Macrobe’ is the word we propose for larger life forms, and we use it as part of an argument for microbial equality. We suggest that taking more notice of microbes – the dominant life form on the planet, both now and throughout evolutionary history – will transform some of the philosophy of biology’s standard ideas on ontology, evolution, taxonomy and biodiversity. We set out a number of recent developments in microbiology – including biofilm formation, chemotaxis, quorum sensing and gene transfer – that highlight microbial capacities for cooperation and communication and break down conventional thinking that microbes are solely or primarily single-celled organisms. These insights also bring new perspectives to the levels of selection debate, as well as to discussions of the evolution and nature of multicellularity, and to neo-Darwinian understandings of evolutionary mechanisms. We show how these revisions lead to further complications for microbial classification and the philosophies of systematics and biodiversity. Incorporating microbial insights into the philosophy of biology will challenge many of its assumptions, but also give greater scope and depth to its investigations