1,497 research outputs found
Heavy Quark Fluorescence
Heavy hadrons containing heavy quarks (for example, Upsilon-mesons) feature a
scale separation between the heavy quark mass (about 4.5 GeV for the b-quark)
and the QCD scale (about 0.3 GeV}) that controls effective masses of lighter
constituents. Therefore, as in ordinary molecules, the de-excitation of the
lighter, faster degrees of freedom leaves the velocity distribution of the
heavy quarks unchanged, populating the available decay channels in
qualitatively predictable ways. Automatically an application of the
Franck-Condon principle of molecular physics explains several puzzling results
of Upsilon(5S) decays as measured by the Belle collaboration, such as the high
rate of Bs*-anti Bs* versus Bs*-anti Bs production, the strength of three-body
B-anti B + pion decays, or the dip in B momentum shown in these decays. We
argue that the data is showing the first Sturm-Liouville zero of the
Upsilon(5S) quantum mechanical squared wavefunction, and providing evidence for
a largely b-anti b composition of this meson.Comment: 4 pages, 4 figures, Figure 2 updated and some typos corrected. To be
published in Physical Review Letter
Thermal Risk Mitigation Testing of the DarkNESS Observatory for Fermi NationalAccelerator Laboratory
This paper presents the prototype design and laboratory test results of the thermal control system for the Dark matter as sterile Neutrino Search Satellite (DarkNESS). A collaboration between Fermilab, CU Aerospace, and the University of Illinois Department of Aerospace Engineering’s Laboratory for Advanced Space Systems (LASSI), the 6U satellite uses a Skipper CCD to detect weak 3.55 – 3.57 keV X-ray emissions, previously discovered by the XMM-Newton and Chandra X-ray observatories. To minimize read-out noise, the thermal control system incorporates a 10 W integral rotary cryocooler and passive heat transfer elements, maintaining the CCD at an operating temperature of 170 K. Analyses of the Earth\u27s obstruction of the instrument’s field of view and the impact of external heating on the instrument aperture established performance requirements and attitude constraints for the thermal control system. A high-fidelity test of a preliminary design was performed in a thermal vacuum chamber, prompting modifications to improve the thermal system design margins. This effort precedes the Critical Design Review milestone
Molecular characterization of a fungal gene paralogue of the penicillin penDE gene of Penicillium chrysogenum
<p>Abstract</p> <p>Background</p> <p><it>Penicillium chrysogenum </it>converts isopenicillin N (IPN) into hydrophobic penicillins by means of the peroxisomal IPN acyltransferase (IAT), which is encoded by the <it>penDE </it>gene. <it>In silico </it>analysis of the <it>P. chrysogenum </it>genome revealed the presence of a gene, Pc13g09140, initially described as paralogue of the IAT-encoding <it>penDE </it>gene. We have termed this gene <it>ial </it>because it encodes a protein with high similarity to IAT (IAL for IAT-Like). We have conducted an investigation to characterize the <it>ial </it>gene and to determine the role of the IAL protein in the penicillin biosynthetic pathway.</p> <p>Results</p> <p>The IAL contains motifs characteristic of the IAT such as the processing site, but lacks the peroxisomal targeting sequence ARL. Null <it>ial </it>mutants and overexpressing strains indicated that IAL lacks acyltransferase (penicillin biosynthetic) and amidohydrolase (6-APA forming) activities <it>in vivo</it>. When the canonical ARL motif (leading to peroxisomal targeting) was added to the C-terminus of the IAL protein (IAL<sup>ARL</sup>) by site-directed mutagenesis, no penicillin biosynthetic activity was detected. Since the IAT is only active after an accurate self-processing of the preprotein into α and β subunits, self-processing of the IAL was tested in <it>Escherichia coli</it>. Overexpression experiments and SDS-PAGE analysis revealed that IAL is also self-processed in two subunits, but despite the correct processing, the enzyme remained inactive <it>in vitro</it>.</p> <p>Conclusion</p> <p>No activity related to the penicillin biosynthesis was detected for the IAL. Sequence comparison among the <it>P. chrysogenum </it>IAL, the <it>A. nidulans </it>IAL homologue and the IAT, revealed that the lack of enzyme activity seems to be due to an alteration of the essential Ser309 in the thioesterase active site. Homologues of the <it>ial </it>gene have been found in many other ascomycetes, including non-penicillin producers. Our data suggest that like in <it>A. nidulans</it>, the <it>ial </it>and <it>penDE </it>genes might have been formed from a single ancestral gene that became duplicated during evolution, although a separate evolutive origin for the <it>ial </it>and <it>penDE </it>genes, is also discussed.</p
Chapter 19. The Blackspot seabream fishery in the Strait of Gibraltar: lessons and future perspectives of shared marine resource
The Blackspot seabream (Pagellus bogaraveo) is one of the most important commercially-exploited fish species for the Spanish and Moroccan fleets which operate in the Strait of Gibraltar. In recent years, landings of Blackspot seabream in the main ports have decreased significantly respect previous periods of maximum catches, which makes it necessary to properly assess the abundance before establishing a management plan to make the fishery sustainable over time. In this chapter, we describe three different approaches to assess the abundance of this species in the Strait of Gibraltar. The results of three approaches tested (LCA/VPA, Gadget model and SimFish model) point out that from the 2010 the stock is kept at very low levels that oscillate between 900 and 1600 t, which supposes that the total biomass is between a 16% and 29% of the potential biomass. Additionally, the reference point values estimated by LCA/VPA and Gadget (F0.1 = 0.12-0.17) imply a clear overexploitation of the resource what is reinforced by the SimFish model results indicating that at least the 64% of abundance variation is a consequence of the fishery component.En prens
Respuesta productiva de gallinas semipesadas inducidas al descanso ovárico en diferentes edades
RESUMEN
Objetivo. Evaluar el efecto de la inducción al descanso ovárico (DO) a diferentes edades sobre la respuesta productiva en aves semipesadas productoras de huevo comercial. Materiales y método. Se usaron 840 aves de la línea Hy Line Brown con 64 semanas de edad, distribuidas en 10 tratamientos, consistentes en tres edades (65, 70 y 75 semanas) con la aplicación de tres períodos de ayuno (5, 10 y 15 días) y un control (sin DO). El análisis estadístico utilizó un modelo completamente aleatorizado, anidado, efecto fijo y balanceado. Se evaluó consumo de calcio durante el ayuno (g/ave/día), consumo de alimento (g/ave/día), porcentaje de producción, peso del huevo (g), conversión por masa de huevo y huevos por ave alojada (HAA). Resultados. La edad presentó efecto significativo (p<0.05) sobre las variables consumo de alimento, día del primer huevo postmuda, días sin producción, día postmuda de retorno al 50% de producción, peso del huevo, número de huevos, masa huevos, conversión y porcentaje de producción (p<0.01). Al comparar con el control, el tratamiento 75-5 presentó efecto significativo (p<0.05) para las variables: consumo de alimento, número de huevos promedio, masa huevos y conversión. Conclusiones. Las aves con mayor período de ayuno presentaron mayor período improductivo postmuda, grandes pérdidas de peso y alto consumo de alimento, lo que genera alta conversión e ineficiencia productiva. En comparación con reportes de literatura sobre DO en aves livianas, las aves semipesadas llegan al cese de producción en menos días y su período improductivo es menor
Analyzing connectivity in collective transportation line networks by means of hypergraphs
In this paper we will show how hypergraphs and some measures related to them can help in extracting information about Collective Transportation Line Networks. We will also prove that these measures satisfy certain properties that validate their use to compare the connectivity of different networks. © 2013 EDP Sciences and Springer.This work was partially supported by Ministerio de Educacion, Ciencia e Innovacion (Spain)/FEDER under project MTM2009-14243 and by Junta de Andalucia (Spain)/FEDER under excellence proyects P09-TEP-5022 and FQM-5849. Special thanks are due to two anonymous referees for their valuable comments and advice.Barrena, E.; De-Los-Santos, A.; Mesa López-Colmenar, JA.; Perea Rojas Marcos, F. (2013). Analyzing connectivity in collective transportation line networks by means of hypergraphs. European Physical Journal - Special Topics. 215(1):93-108. https://doi.org/10.1140/epjst/e2013-01717-3S931082151D.J. Watts, S.H. Strogatz, Nature 393, 440 (1998)V. Latora, M. Marchiori, Phys. Rev. Lett. 87, 198701 (2001)V. Latora, M. Marchiori, Physica A 314, 109 (2002)R. Criado, B. Hernández-Bermejo, M. Romance, Int. J. Bifurcation Chaos 17, 2289 (2007)A. De-Los-Santos, G. Laporte, J.A. Mesa, F. Perea, Transp. Res. Part C: Emerging Technol. 20, 34 (2012)E. Barrena, A. De-Los-Santos, J.A. Mesa, F. Perea, Technical proofs of paper “Analyzing Connectivity in Collective Transportation Line Networks by means of Hypergraphs”, http://grupo.us.es/transfers/ (2012)C. Berge, Graphs and Hypergraphs (Elsevier Science Ltd., 1985)C. Berge, Hypergraphs: combinatorics of finite sets (North Holland)D.J. Watts, Small Worlds: The Dynamics of Networks between Order and Randomness (Princeton University Press, Princeton, 1999), p. 262M.E.J. Newman, Technical report, Santa Fe Institute (2001)M.E.J. Newman, Phys. Rev. E 64, 016131 (2001)M.E.J. Newman, Phys. Rev. E 64, 016132 (2001)E. Estrada, J.A. Rodríguez-Velázquez, Phys. A: Statist. Mech. Appl. 364, 581 (2006)R. Dechter, Constraint Processing (Morgan Kaufmann, 2003), p. 450P. Sen, S. Dasgupta, A. Chatterjee, P.A. Sreeram, G. Mukherjee, S.S. Manna, Phys. Rev. E 67 (2003)P. Crucitti, V. Latora, M. Marchiori, A. Rapisarda, Physica A 320, 642 (2002) [cond-mat/0205601]V. Latora, M. Marchiori, Chaos Solitons Fract. 20, 69 (2004)V. Latora, M. Marchiori, Eur. Phys. J. B 32, 249 (2002
Transcriptional upregulation of four genes of the lysine biosynthetic pathway by homocitrate accumulation in Penicillium chrysogenum: homocitrate as a sensor of lysine-pathway distress
The lysine biosynthetic pathway has to supply large amounts of α-aminoadipic acid for penicillin biosynthesis in Penicillium chrysogenum. In this study, we have characterized the P. chrysogenum L2 mutant, a lysine auxotroph that shows highly increased expression of several lysine biosynthesis genes (lys1, lys2, lys3, lys7). The L2 mutant was found to be deficient in homoaconitase activity since it was complemented by the Aspergillus nidulans lysF gene. We have cloned a gene (named lys3) that complements the L2 mutation by transformation with a P. chrysogenum genomic library, constructed in an autonomous replicating plasmid. The lys3-encoded protein showed high identity to homoaconitases. In addition, we cloned the mutant lys3 allele from the L2 strain that showed a G1534 to A1534 point mutation resulting in a Gly495 to Asp495 substitution. This mutation is located in a highly conserved region adjacent to two of the three cysteine residues that act as ligands to bind the iron-sulfur cluster required for homoaconitase activity. The L2 mutant accumulates homocitrate. Deletion of the lys1 gene (homocitrate synthase) in the L2 strain prevented homocitrate accumulation and reverted expression levels of the four lysine biosynthesis genes tested to those of the parental prototrophic strain. Homocitrate accumulation seems to act as a sensor of lysine-pathway distress, triggering overexpression of four of the lysine biosynthesis genes.Fil: Teves, Franco. Universidad de León; EspañaFil: Lamas Maceiras, Mónica. Universidad de León; EspañaFil: García Estrada, Carlos. Instituto de Biotecnología de León; EspañaFil: Casqueiro, Javier. Instituto de Biotecnología de León; España. Universidad de León; EspañaFil: Naranjo, Leopoldo. Universidad de León; EspañaFil: Ullán, Ricardo V.. Instituto de Biotecnología de León; EspañaFil: Scervino, Jose Martin. Instituto de Biotecnología de León; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Wu, Xiaobin. Instituto de Biotecnología de León; EspañaFil: Velasco Conde, Tania. Instituto de Biotecnología de León; EspañaFil: Martín, Juan F.. Instituto de Biotecnología de León; España. Universidad de León; Españ
Influence of seamounts on control and triggering tsunamis in the Alboran basin (continental margins)
Plaque-Associated Oligomeric Amyloid-Beta Drives Early Synaptotoxicity in APP/PS1 Mice Hippocampus: Ultrastructural Pathology Analysis
Alzheimer’s disease (AD) is a devastating neurodegenerative disorder characterized by initial memory impairments that progress to dementia. In this sense, synaptic dysfunction and loss have been established as the pathological features that best correlate with the typical early cognitive decline in this disease. At the histopathological level, post mortem AD brains typically exhibit intraneuronal neurofibrillary tangles (NFTs) along with the accumulation of amyloid-beta (Abeta) peptides in the form of extracellular deposits. Specifically, the oligomeric soluble forms of Abeta are considered the most synaptotoxic species. In addition, neuritic plaques are Abeta deposits surrounded by activated microglia and astroglia cells together with abnormal swellings of neuronal processes named dystrophic neurites. These periplaque aberrant neurites are mostly presynaptic elements and represent the first pathological indicator of synaptic dysfunction. In terms of losing synaptic proteins, the hippocampus is one of the brain regions most affected in AD patients. In this work, we report an early decline in spatial memory, along with hippocampal synaptic changes, in an amyloidogenic APP/PS1 transgenic model. Quantitative electron microscopy revealed a spatial synaptotoxic pattern around neuritic plaques with significant loss of periplaque synaptic terminals, showing rising synapse loss close to the border, especially in larger plaques. Moreover, dystrophic presynapses were filled with autophagic vesicles in detriment of the presynaptic vesicular density, probably interfering with synaptic function at very early synaptopathological disease stages. Electron immunogold labeling showed that the periphery of amyloid plaques, and the associated dystrophic neurites, was enriched in Abeta oligomers supporting an extracellular location of the synaptotoxins. Finally, the incubation of primary neurons with soluble fractions derived from 6-month-old APP/PS1 hippocampus induced significant loss of synaptic proteins, but not neuronal death. Indeed, this preclinical transgenic model could serve to investigate therapies targeted at initial stages of synaptic dysfunction relevant to the prodromal and early AD.This study was supported by the Instituto de Salud Carlos III (ISCiii) of Spain, co-financed by the FEDER funds from European Union, through grants PI18/01557 (to AG) and PI18/01556 (to JV); by the Junta de Andalucia Consejería de Economía y Conocimiento through grants UMA18-FEDERJA-211 (to AG), P18-RT-2233 (to AG), and US-1262734 (to JV) co-financed by Programa Operativo FEDER 2014–2020; by the Spanish Minister of Science and Innovation grant PID2019-108911RA-100 (to DB-V), Beatriz Galindo program BAGAL18/00052 (to DB-V) grant PID2019-107090RA-I00 (to IM-G), and Ramon y Cajal Program RYC-2017-21879 (to IM-G); and by the Malaga University grants B1-2019_07 (to ES-M) and B1-2019_06 (to IM-G). MM-O held a predoctoral contract from Malaga University and ES-M a postdoctoral contract (DOC_00251) from Junta de Andalucia
Submarine canyons and related features in the Alboran Sea: continental margins and major isolated reliefs
The analysis of a data set of multibeam bathymetry plus high resolution seismic and parametric
profiles allow us to characterize the geomorphologic units on the Alboran Sea-floor as well as the
evolution of morpho-sedimentary systems along the Pliocene and Quaternary, later than the main
erosive Messinian event. Since the opening of the Gibraltar Straits, the sedimentary evolution of
this basin has been controlled by the interchange of water masses between the Atlantic Ocean and
the Mediterranean Sea. Basin physiography is also a consequence of the Pliocene-Quaternary
compression which has progressively uplifted the sourrounding reliefs and deforms the interior and
the margins of the basin. On this scenario, several submarine canyons and gullies have been
developed in this basin which traverse especially the northern margin and the flanks of the Northern
Alboran Ridge, without affecting the African margins. This fact must be related to the action of
bottom contour currents which constitute the main morpho-sedimentary process. The influence
of water masses distributed the sedimentary input carried by rivers and coming from the erosion
of surrounding ranges. In the southern margin of this basin this influence is stronger and inhibits
the development of transversal submarine canyons
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