Fitoplancton de dos lagunas de los humedalesde Xeresa y Xeraco (Valencia, España).

VILLENA, M. J. & ROMO, S. 2001. Fitoplancton de dos lagunas de los humedales de Xeresa y Xeraco (Valencia, España). Bot. Complutensis 25: 179-189. Se ha estudiado la composición fitoplanctónica de dos lagunas costeras mediterráneas, que corresponden a los marjales de Xeresa y Xeraco (Valencia). Estas zonas húmedas de la Comunidad Valenciana poseen un importante valor ecológico y botánico para nuestra Península, aunque actualmente se encuentran amenazadas por transformaciones de tipo turístico o agrícola. Las lagunas estudiadas se caracterizan por ser someras (Zmax: 3 m), oligohalinas, de aguas transparentes y mesotróficas, y por encontrarse sobre lechos de turba y con praderas de macrófitos sumergidos. El fitoplancton observado destaca por presentar una composición similar para ambas lagunas, con especies cosmopolitas y abundancia de microalgales de pequeño tamaño. Esta estructura de tamaño resulta importante para mantener las complejas redes tróficas de estos lagos someros. El grupo algal más diverso, en ambas lagunas, fue el de las clorofíceas. Sin embargo, la abundancia y biomasa algal fue acaparada por las cianofíceas filamentosas en la laguna de Xeresa, mientras que las clorofíceas y criptofíceas dominaron en la laguna de Cap de Terme.VILLENA, M. J. & ROMO, S. 2001. Phytoplankton from two lakes of Xeresa and Xeraco wetlands (Valencia, Spain). Bot. Complutensis 25: 179-189. Phytoplankton composition from two Mediterranean Coastal lakes located in Xeresa and Xeraco wetlands (Valencia, Spain) were studied. These wetlands from the Comunidad Valenciana have an important ecological and botanical value for the Iberian Peninsula, although nowadays they are threatened by turistic and agriculture development. The study lakes are characterized to be shallow (Zmax: 3 m), oligohaline, water transparent, mesotrophic and peat lakes, which are covered by sumerged macrophytes. The phytoplankton observed was similar in both lakes, with cosmopolitan species and abundant small-size microalgae. This size structure is relevant for the maintenance of the complex food-webs of these shallow la 179 M. J. Villena & S. Romo Fitoplancton de dos lagunas de los humedales de Xeresa... kes. The most diverse algal group, in both study lakes, corresponded to chlorophytes. However, the algal abundance and biomasa was overwhelmed by cyanophytes in the lake of Xeresa, but by chlorophytes and cryptophytes in the lake of Cap de Terme

Biosphere 2 test module experimentation program

The Biosphere 2 Test Module is a facility which has the capability to do either short or long term closures: five month closures with plants were conducted. Also conducted were investigations of specific problems, such as trace gas purification by bioregenerative systems by in-putting a fixed concentration of a gas and observing its uptake over time. In other Test Module experiments, the concentration of one gas was changed to observe what effects this has on other gases present or on the system. The science of biospherics which encompasses the study of closed biological systems provides an opening into the future in space as well as in the Earth's biosphere

Rare top decay and CP violation in THDM

We discuss the formalism of two Higgs doublet model type III with CP violation from CP-even CP-odd mixing in the neutral Higgs bosons. The flavor changing interactions among neutral Higgs bosons and fermions are presented at tree level in this type of model. These assumptions allow the study rare top decays mediated by neutral Higgs bosons, particularly we are interested in $t\rightarrow c l^+l^-$. For this process we estimated upper bounds of the branching ratios $\textrm{Br}(t\rightarrow c \tau^+\tau^-)$ of the order of $10^{-9}\sim 10^{-7}$ for a neutral Higgs boson mass of 125 GeV and $\tan\beta=1$, 1.5, 2, 2.5. For the case of $t\rightarrow c \tau^+\tau^-$ the number of possible events is estimated from 1 to 10 events which could be observed in future experiments at LHC with a luminosity of 300 $\textrm{fb}^{-1}$ and 14 GeV for the energy of the center of mass. Also we estimate that the number of events for the process $t\rightarrow c l^+l^-$ in different scenarios is of order of $2500$.Comment: 8 pages, 5 figure

Dipper-Donkin algebra as global symmetry of quantum chains

We analize the role of GL_2, a quantum group constructed by Dipper-Donkin, as a global symmetry for quantum chains, and show the way to construct all possible Hamiltonians for four states quantum chains with GL_2 global symmetry. In doing this, we search all inner actions of GL_2 on the Clifford algebra C(1,3) and show them. We also introduce the corresponding operator algebras, invariants and Hamiltonians, explicitly.Comment: 30 pages, 3 Figures, LaTex2

A-branes, foliations and localization

This paper studies a notion of enumerative invariants for stable $A$-branes,and discusses its relation to invariants defined by spectral and exponentialnetworks. A natural definition of stable $A$-branes and their counts isprovided by the string theoretic origin of the topological $A$-model. This isthe Witten index of the supersymmetric quantum mechanics of a single $D3$ branesupported on a special Lagrangian in a Calabi-Yau threefold. Geometrically,this is closely related to the Euler characteristic of the $A$-brane modulispace. Using the natural torus action on this moduli space, we reduce thecomputation of its Euler characteristic to a count of fixed points viaequivariant localization. Studying the $A$-branes that correspond to fixedpoints, we make contact with definitions of spectral and exponential networks.We find agreement between the counts defined via the Witten index, and the BPSinvariants defined by networks. By extension, our definition also matches withDonaldson-Thomas invariants of $B$-branes related by homological mirrorsymmetry.<br

A Fresh Look at Huntingtin mRNA Processing in Huntington\u27s Disease

Huntington\u27s disease (HD) is an inherited neurodegenerative disorder caused by a mutation that expands the polyglutamine (CAG) repeat in exon 1 of the huntingtin (HTT) gene. Wild-type HTT protein interacts with other proteins to protect cells against toxic stimuli, mediate vesicle transport and endocytosis, and modulate synaptic activity. Mutant HTT protein disrupts autophagy, vesicle transport, neurotransmitter signaling, and mitochondrial function. Although many of the activities of wild-type HTT protein and the toxicities of mutant HTT protein are characterized, less is known about the activities of HTT mRNA. Most putative HD therapies aim to target mutant HTT mRNA before it is translated into the protein. Therefore, it is imperative to learn as much as we can about how cells handle both wild-type and mutant HTT mRNA so that effective therapies can be designed. Here, we review the structure of wild-type and mutant HTT mRNA, with emphasis on their alternatively polyadenylated or spliced isoforms. We then consider the abundance of HTT mRNA isoforms in HD and discuss the potential implications of these findings. Evidence in the review should be used to guide future research aimed at developing mRNA-lowering therapies for HD