2,662 research outputs found
Cosmic Ray Physics with ACORDE at LHC
The use of large underground high-energy physics experiments, for comic ray
studies, have been used, in the past, at CERN, in order to measure, precisely,
the inclusive cosmic ray flux in the energy range from 2x10^10 - 2x10^12 eV.
ACORDE, ALICE Cosmic Rays DEtector, will act as Level 0 cosmic ray trigger and,
together with other ALICE apparatus, will provide precise information on cosmic
rays with primary energies around 10^15 - 10^17 eV. This paper reviews the main
detector features, the present status, commissioning and integration with other
apparatus. Finally, we discuss the ACORDE-ALICE cosmic ray physics program.Comment: Contribution to the 2007 Europhysics Conference on High Energy
Physics - Manchester, England 19-25 July 2007; 3 pages, 3 figure
Diversity of free-living ciliates in the sandy sediment of a Spanish stream in winter
This study had two objectives: to determine the number of (phenotypic) ciliate species co-existing in 1 m2 of sandy
river sediment at a maximum temperature of 4 "C; and to determine the ecological mechanism(s) facilitating their
co-existence. The ciliate community was diverse (65 species [8 of which are new], belonging to 50 genera, from 17
orders). The sediment supported a superficial mat of diatoms (> 30 species). These served as food for at least 16
ciliate species. The size frequency distribution of ingested diatoms was almost identical to that for the diatoms in the sediment: thus the probability of a diatom being ingested appears to be a simple function of its relative abundance. Two factors were probably important for the co-existence of ciliate species : wide variation in cell size and shape enabled them to occupy most habitats; and they deployed a variety of feeding mechanisms to consume
the variety of microbial food types. Taken as a whole, the ciliate community was capable of feeding on all microbes,
including other protozoa, up to a size of about 80 pm. Considering the broad diversity of ciliate habitats available within 1 m2, the importance of physical transport processes in the river basin, and the known cosmopolitan
distribution of many ciliate species, it is believed likely that the species richness we recorded is representative of
the expanse of sandy sediment in this river, on this occasion
Copolymers of glutamic acid and tyrosine are potent inhibitors of oocyte casein kinase II
AbstractPolypeptides rich in glutamic acid are strong inhibitors purified from isolated nuclei of Xenopus laevis oocytes of casein kinase II. The presence of tyrosine in these peptides greatly enhances their inhibitory capacity. Using casein as a substrate, copolyglu:tyr (4:1) has an I50 value of 20 nM, 250 fold lower than that of polyglutamic acid which is 5 μM. A similar large difference is observed when a synthetic peptide is used as substrate. The inhibition of copolyglu:tyr is competitive with casein and can be completely reversed by high ionic strength. The relative inhibitory capacity of the polypeptides tested, in descending order, is copolyglu:tyr (4:1) > copolyglu:tyr (1:1) > polyglu > copolyglu:phe (4:1) > copolyglu:ala ( > copolyglu:leu (4:1). The high affinity for tyrosine-containing acid peptides is shared by rat liver and yeast casein kinase II so that it seems to be a general property of these enzymes
EL AHORRO DE LOS HOGARES EN COLOMBIA
En este documento se presenta un análisis del comportamiento del ahorro de los hogares y sus determinantes, considerando una perspectiva de largo plazo para el periodo 1950-2004 y una de corto plazo a nivel microeconómico, utilizando la información de las encuestas de calidad de vida de 1997 y 2003. A nivel agregado, con base en un análisis de cointegración se encontró una relación de largo plazo entre la tasa de ahorro de los hogares, el PIB per-cápita, los impuestos directos y una medida de profundización financiera. A nivel microeconómico, se realiza un análisis de las tasas de ahorro agrupadas por diferentes características socioeconómicas de los hogares y para diferentes definiciones de ahorro considerando la inversión en capital humano y la compra de bienes durables. Adicionalmente, se presenta un análisis del comportamiento del ahorro a partir de la hipótesis del ciclo de vida, utilizado los perfiles de ahorro por año de nacimiento del jefe del hogar. Los resultados muestran que tanto el ingreso como el consumo registran un comportamiento de U invertida, sugiriendo que para el caso Colombiano no hay evidencia de que se cumpla la hipótesis del ciclo de vida. Finalmente, al comparar los datos de ahorro de los hogares a nivel agregado, con los datos obtenidos a partir de la información de las encuestas se encuentran diferencias que se pueden explicar por razones metodológicas y por el cambio en la distribución de los ingresos y de los gastos registrado entre 1997 y 2003.Ahorro de los hogares, hipótesis de ciclo de vida, consumo, Colombia. Classification JEL:D12; D19; E01; E21.
Hearing Loss after Discontinuing Secondary Prophylaxis for Cryptococcal Meningitis: Relapse or Immune Reconstitution?
Relapse and immune reconstitution syndrome are difficult to distinguish in HIV-infected patients treated with antiretroviral therapy (ART). We report on a 26-year-old HIV-infected male (CDC C3) with hearing loss on the right side 2 months after discontinuing secondary prophylaxis for cryptococcal meningitis. CD4 cell counts had increased from 32/µl to stable counts > 200/µl for the preceding 6 months on ART but HIV replication was not fully suppressed (7,000 copies/ml). Magnetic resonance imaging identified lesions at the origin of the right cranial nerve VIII. Lumbar puncture revealed monocytic pleocytosis, slightly increased protein, but normal glucose and lactate levels, negative microbiological studies. Fluconazole was restarted and a new ART regimen was started in order to fully suppress HIV replication. Clinical and radiological signs were reversible during follow-up, and secondary prophylaxis was stopped after 6 months without adverse events. We review 26 published cases of cryptococcal infections with immune reconstitution syndrome and highlight the distinguishing feature
Phytochemical, antioxidant and antimicrobial parameters of essential oils and hydrosols of colombian Thyme and Rosemary obtained using two different steam distillation methods
Two procedures of steam distillation of Rosmarinus officinalis and Thymus vulgaris were compared by phytochemical, antioxidant and antimicrobial analysis of their respective essential oils and hydrosols using respectively GCFID and GCMS analysis, free radical scavenging activity on ABTS and dilution and diffusion method against 3 bacteria and 2 fungi. Differences in bioactivity results are discussed taking into account changes in molecular content of essential oils and hydrosols obtained by the two different distillation methods. Although no significant difference was observed between the two procedures with Rosmarinus officinalis, that was not the case with Thymus vulgaris. Significant differences were noted, not only in their respective chemical composition especially with the thymol and p-cymene percentage with respectively a change from 39% with conventional steam distillation to 27% with adapted steam distillation for thymol and from 28% with the first distillation to 37% with the second one for p-cymene. These phytochemical composition changes have an impact on their biological activities results and consequently on the therapeutic activities expected which shows the importance of distillation method selection
Effect of Power Control Imperfections on the Reverse Link of Cellular CDMA Networks Under Multipath Fading
Belastungsabhängige vertikale Doppelbilder und Ptosis
Zusammenfassung: Eine 43-jährige Patientin wurde uns vorgestellt, da seit 2-3Monaten ihr linkes Augenlid in wechselnder Ausprägung hing. Ferner nahm sie auch Doppelbilder in Extrempositionen oder nach schnellen Augenbewegungen wahr und war lichtempfindlich. Die Diagnose ergab ein Keilbeinmeningeom. Es wurde in der Folge 2-mal innerhalb von 3Monaten mittels Radiopeptidtherapie mit 90Y-DOTATOC (Somatostatin-Analogon) behandelt. Bei unserer Patientin führte diese Therapie zu einer Volumenreduktion des Tumors sowie zu einer klinischen Verbesserung und dann Stabilisierun
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