Z_p scalar dark matter from multi-Higgs-doublet models

in Physical Review. D : Particles and Fields (2012), 86(1), 0160047

In many models, stability of dark matter particles is protected by a conserved Z_2 quantum number. However dark matter can be stabilized by other discrete symmetry groups, and examples of such models with ... [more ▼]

In many models, stability of dark matter particles is protected by a conserved Z_2 quantum number. However dark matter can be stabilized by other discrete symmetry groups, and examples of such models with custom-tailored field content have been proposed. Here we show that electroweak symmetry breaking models with N Higgs doublets can readily accommodate scalar dark matter candidates stabilized by groups Z_p with any $p \le 2^{N-1}$, leading to a variety of kinds of microscopic dynamics in the dark sector. We give examples in which semi-annihilation or multiple semi-annihilation processes are allowed or forbidden, which can be especially interesting in the case of asymmetric dark matter. [less ▲]

Zaburzenia przebiegu okresu poporodowego

in Gajewski, Zdzislaw (Ed.) Problemy w rozrodzie bydla - Aktualne poglady. (2011, May 28)

The Zápara Indians : the Consecration of an Endangered People

in Museum International (2003), 55(2), 25-30

Focuses on the United Nations Educational, Scientific and Cultural Organization's (UNESCO) declaration of the oral heritage and cultural manifestations of the Zápara people of Amazonia as a 'Masterpiece ... [more ▼]

Focuses on the United Nations Educational, Scientific and Cultural Organization's (UNESCO) declaration of the oral heritage and cultural manifestations of the Zápara people of Amazonia as a 'Masterpiece of the Oral and Intangible Heritage of Humanity.' Impact that the UNESCO recognition has had on the Zápara; Details of how the Zápara were able to secure sacred status from the UNESCO. [less ▲]

Zapatisten strijden voor emancipatie Indianen

Article for general public (1998)

Zastosowanie ultrasonografii w diagnostyce klinicznej ukladu rozrodczego u bydla

in Nowa Weterynaria (1997)

Zavalíaite, (M,2+,Fe2+,Mg)3(PO4)2, a new primary phosphate from the La Empleada pegmatite, San Luis Province, Argentina.

in Abstract Book (2012)

A zealous parallel gradient descent algorithm

Poster (2010, December 11)

Parallel and distributed algorithms have become a necessity in modern machine learning tasks. In this work, we focus on parallel asynchronous gradient descent and propose a zealous variant that minimizes ... [more ▼]

Parallel and distributed algorithms have become a necessity in modern machine learning tasks. In this work, we focus on parallel asynchronous gradient descent and propose a zealous variant that minimizes the idle time of processors to achieve a substantial speedup. We then experimentally study this algorithm in the context of training a restricted Boltzmann machine on a large collaborative filtering task. [less ▲]

Zebrafish as model in toxicology/pharmacology.

Poster (2010, March 17)

The zebrafish genome encodes the largest vertebrate repertoire of functional aquaporins with dual paralogy and substrate specificities similar to mammals

in BMC Evolutionary Biology (2010), 10

Background: Aquaporins are integral membrane proteins that facilitate the transport of water and small solutes across cell membranes. These proteins are vital for maintaining water homeostasis in living ... [more ▼]

Background: Aquaporins are integral membrane proteins that facilitate the transport of water and small solutes across cell membranes. These proteins are vital for maintaining water homeostasis in living organisms. In mammals, thirteen aquaporins (AQP0-12) have been characterized, but in lower vertebrates, such as fish, the diversity, structure and substrate specificity of these membrane channel proteins are largely unknown. Results: The screening and isolation of transcripts from the zebrafish (Danio rerio) genome revealed eighteen sequences structurally related to the four subfamilies of tetrapod aquaporins, i.e., aquaporins (AQP0, -1 and -4), water and glycerol transporters or aquaglyceroporins (Glps; AQP3 and AQP7-10), a water and urea transporter (AQP8), and two unorthodox aquaporins (AQP11 and -12). Phylogenetic analyses of nucleotide and deduced amino acid sequences demonstrated dual paralogy between teleost and human aquaporins. Three of the duplicated zebrafish isoforms have unlinked loci, two have linked loci, while DrAqp8 was found in triplicate across two chromosomes. Genomic sequencing, structural analysis, and maximum likelihood reconstruction, further revealed the presence of a putative pseudogene that displays hybrid exons similar to tetrapod AQP5 and -1. Ectopic expression of the cloned transcripts in Xenopus laevis oocytes demonstrated that zebrafish aquaporins and Glps transport water or water, glycerol and urea, respectively, whereas DrAqp11b and -12 were not functional in oocytes. Contrary to humans and some rodents, intrachromosomal duplicates of zebrafish AQP8 were water and urea permeable, while the genomic duplicate only transported water. All aquaporin transcripts were expressed in adult tissues and found to have divergent expression patterns. In some tissues, however, redundant expression of transcripts encoding two duplicated paralogs seems to occur. Conclusion: The zebrafish genome encodes the largest repertoire of functional vertebrate aquaporins with dual paralogy to human isoforms. Our data reveal an early and specific diversification of these integral membrane proteins at the root of the crown-clade of Teleostei. Despite the increase in gene copy number, zebrafish aquaporins mostly retain the substrate specificity characteristic of the tetrapod counterparts. Based upon the integration of phylogenetic, genomic and functional data we propose a new classification for the piscine aquaporin superfamily. [less ▲]

The zebrafish Sox4b transcription factor activates pituitary expression of gata2 and specification of thyrotropes and gonadotropes.

Poster (2010)