1,717 research outputs found

    Marketing Agreements and Orders for Texas Fruits and Vegetables.

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    6 p

    Does coevolution promote species richness in parasitic cuckoos?

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    Why some lineages have diversified into larger numbers of species than others is a fundamental but still relatively poorly understood aspect of the evolutionary process. Coevolution has been recognized as a potentially important engine of speciation, but has rarely been tested in a comparative framework. We use a comparative approach based on a complete phylogeny of all living cuckoos to test whether parasite–host coevolution is associated with patterns of cuckoo species richness. There are no clear differences between parental and parasitic cuckoos in the number of species per genus. However, a cladogenesis test shows that brood parasitism is associated with both significantly higher speciation and extinction rates. Furthermore, subspecies diversification rate estimates were over twice as high in parasitic cuckoos as in parental cuckoos. Among parasitic cuckoos, there is marked variation in the severity of the detrimental effects on host fitness; chicks of some cuckoo species are raised alongside the young of the host and others are more virulent, with the cuckoo chick ejecting or killing the eggs/young of the host. We show that cuckoos with a more virulent parasitic strategy have more recognized subspecies. In addition, cuckoo species with more recognized subspecies have more hosts. These results hold after controlling for confounding geographical effects such as range size and isolation in archipelagos. Although the power of our analyses is limited by the fact that brood parasitism evolved independently only three times in cuckoos, our results suggest that coevolutionary arms races with hosts have contributed to higher speciation and extinction rates in parasitic cuckoos

    Transmission Properties of the oscillating delta-function potential

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    We derive an exact expression for the transmission amplitude of a particle moving through a harmonically driven delta-function potential by using the method of continued-fractions within the framework of Floquet theory. We prove that the transmission through this potential as a function of the incident energy presents at most two real zeros, that its poles occur at energies nω+εn\hbar\omega+\varepsilon^* (0<Re(ε)<ω0<Re(\varepsilon^*)<\hbar\omega), and that the poles and zeros in the transmission amplitude come in pairs with the distance between the zeros and the poles (and their residue) decreasing with increasing energy of the incident particle. We also show the existence of non-resonant "bands" in the transmission amplitude as a function of the strength of the potential and the driving frequency.Comment: 21 pages, 12 figures, 1 tabl

    Discriminación por razón de género y negociación colectiva tras la ley 3/2012

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    Este artículo describe y analiza la configuración jurídica del convenio colectivo como fuente reguladora y ga-rantista del derecho de igualdad y no dis-criminación por razón de género, tanto con carácter general como en el ámbito específico del acceso al empleo, formación y promoción en el trabajo y en las más relevantes condiciones en las relaciones laborales. A tal fin, y a partir de la doctrina establecida por la jurisprudencia constitucional, se estudian las causas de la desigualdad y las categorías que permiten una fundamentación razonable y objetiva para lograr la igualdad material. También se aportan datos cuantitativos acerca de la influencia de la Ley Orgánica 3/2007 en el régimen de los convenios convenios colectivos en esta materia.This paper work de-scribes and analyses the collective agree-ments legal configuration as regulating and guarantor source of the equality's right and no discrimination because of the sex, as much in general terms as in the specific field of accessing to a job, training and advance-ment in the job and in the main conditions in the labour relationships. According the established doctrine by the constitutional sentences, we study the inequality causes and the categories which give a reasonable and factual basis to reach a material equality. In addition, this work also provides quanti-tative facts about the influence of Organic Law 3/2007 in the collective agreements regime in this matte

    Inhibition of angiogenesis and suppression of colorectal cancer metastatic to the liver using the Sleeping Beauty Transposon System

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    <p>Abstract</p> <p>Background</p> <p>Metastatic colon cancer is one of the leading causes of cancer-related death worldwide, with disease progression and metastatic spread being closely associated with angiogenesis. We investigated whether an antiangiogenic gene transfer approach using the <it>Sleeping Beauty </it>(SB) transposon system could be used to inhibit growth of colorectal tumors metastatic to the liver.</p> <p>Results</p> <p>Liver CT26 tumor-bearing mice were hydrodynamically injected with different doses of a plasmid containing a transposon encoding an angiostatin-endostatin fusion gene (Statin AE) along with varying amounts of SB transposase-encoding plasmid. Animals that were injected with a low dose (10 μg) of Statin AE transposon plasmid showed a significant decrease in tumor formation only when co-injected with SB transposase-encoding plasmid, while for animals injected with a higher dose (25 μg) of Statin AE transposon, co-injection of SB transposase-encoding plasmid did not significantly affect tumor load. For animals injected with 10 μg Statin AE transposon plasmid, the number of tumor nodules was inversely proportional to the amount of co-injected SB plasmid. Suppression of metastases was further evident in histological analyses, in which untreated animals showed higher levels of tumor cell proliferation and tumor vascularization than animals treated with low dose transposon plasmid.</p> <p>Conclusion</p> <p>These results demonstrate that hepatic colorectal metastases can be reduced using antiangiogenic transposons, and provide evidence for the importance of the transposition process in mediating suppression of these tumors.</p

    Novel mutations in TARDBP (TDP-43) in patients with familial amyotrophic lateral sclerosis.

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    The TAR DNA-binding protein 43 (TDP-43) has been identified as the major disease protein in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin inclusions (FTLD-U), defining a novel class of neurodegenerative conditions: the TDP-43 proteinopathies. The first pathogenic mutations in the gene encoding TDP-43 (TARDBP) were recently reported in familial and sporadic ALS patients, supporting a direct role for TDP-43 in neurodegeneration. In this study, we report the identification and functional analyses of two novel and one known mutation in TARDBP that we identified as a result of extensive mutation analyses in a cohort of 296 patients with variable neurodegenerative diseases associated with TDP-43 histopathology. Three different heterozygous missense mutations in exon 6 of TARDBP (p.M337V, p.N345K, and p.I383V) were identified in the analysis of 92 familial ALS patients (3.3%), while no mutations were detected in 24 patients with sporadic ALS or 180 patients with other TDP-43-positive neurodegenerative diseases. The presence of p.M337V, p.N345K, and p.I383V was excluded in 825 controls and 652 additional sporadic ALS patients. All three mutations affect highly conserved amino acid residues in the C-terminal part of TDP-43 known to be involved in protein-protein interactions. Biochemical analysis of TDP-43 in ALS patient cell lines revealed a substantial increase in caspase cleaved fragments, including the approximately 25 kDa fragment, compared to control cell lines. Our findings support TARDBP mutations as a cause of ALS. Based on the specific C-terminal location of the mutations and the accumulation of a smaller C-terminal fragment, we speculate that TARDBP mutations may cause a toxic gain of function through novel protein interactions or intracellular accumulation of TDP-43 fragments leading to apoptosis

    Solving path planning problems in urban environments based on a priori sensor availability and execution error propagation

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    This paper addresses safe path planning problem in urban environments under onboard sensor availability uncertainty. In this context, an approach based on Mixed-Observability Markov Decision Process (MOMDP) is presented. Such a model enables the planner to deal with a priori probabilistic sensor availability and path execution error propagation, the which depends on the navigation solution. Due to modelling particularities of this safe path planning problem, such as bounded hidden and fully observable state variables, discrete actions and particular transition function form, the belief state update function becomes a complex step that cannot be ignored during planning. Recent advances in Partially Observable Markov Decision Process (POMDP) solving have proposed a planning algorithm called POMCP, which is based on Monte-Carlo Tree Search method. It allows the planner to work on the history of the action-observation pairs without the need to compute belief state updates. Thereby, this paper proposes to apply a POMCP-like algorithm to solve the addressed MOMDP safe path planning problem. The obtained results show the feasibility of the approach and the impact of considering different a priori probabilistic sensor availability on the result policy
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