986 research outputs found
A halo event created at 200 m above the Chacaltaya emulsion chamber
The results of analysis on a cosmic-ray induced nuclear event with the total visible energy approx. = 1300 TeV which is characterized by the central (halo) part of a strong energy concentration and the outer part of a large lateral spread are presented. The event (named as P06) was detected in the 18th two-storied emulsion chamber exposed at Chacaltaya by Brasil-Japan Collaboration. As the nuclear emulsion plates were inserted at every layer of the concerned blocks in the upper and the lower chambers together with RR- and N-type X-ray films, it is possible to study the details of the event. Some results on P06 have already been reported 1 based on the general measurement of opacity on N-type X-ray films: (1) the total energy of halo is approx. = 1000 TeV; (2) the shower transition reaches its maximum at approx. 16 cu; and (3) the radius of halo is 6.5 mm (at the level of 10 to the 6th power electrons/sq.cm.). The results in more details will be described
A binocular-type atmospheric interaction generating sequential exotic features
A cosmic-ray induced nuclear event is presented, which is of clear binocular-type and contains several exotic features through its passage in the atmosphere and the emulsion chamber
Atmospheric interactions detected in both the upper and the lower chambers at Chacaltaya
The cosmic ray interactions in the energy region 10 to the 13th power to 10 to the 17th power eV were studied by emulsion chambers exposed at Chacaltaya, 5220 m above sea-level. The chambers have a two-storied structure, and the events observed in both chambers give important informations on these phenomena. The first Centauro event was detected as a small shower at the bottom of the upper chamber and as a big fraction of energy deposit in the lower chamber, which indicates a high contribution of hadronic showers. Results of the events with continuation in the rather low energy region are described
A Non-Intrusive GMA Welding Process Quality Monitoring System Using Acoustic Sensing
Most of the inspection methods used for detection and localization of welding disturbances are based on the evaluation of some direct measurements of welding parameters. This direct measurement requires an insertion of sensors during the welding process which could somehow alter the behavior of the metallic transference. An inspection method that evaluates the GMA welding process evolution using a non-intrusive process sensing would allow not only the identification of disturbances during welding runs and thus reduce inspection time, but would also reduce the interference on the process caused by the direct sensing. In this paper a nonintrusive method for weld disturbance detection and localization for weld quality evaluation is demonstrated. The system is based on the acoustic sensing of the welding electrical arc. During repetitive tests in welds without disturbances, the stability acoustic parameters were calculated and used as comparison references for the detection and location of disturbances during the weld runs
Synthesis of a new chiral bis-arsine ligand based on natural carbohydrates
Transition-metal-catalyzed asymmetric allylic substitutions have become one of the most powerful tools for asymmetric C−C bond formation.1 Chiral diphosphine ligands have been some of the largest classes of ligands used in asymmetric substitutions.
Trost developed the chiral ligand, which played a crucial role in the improvement of Pdcatalyzed asymmetric substitutions.2 Based on the Trost modular ligand (TML) system 3 a family of ligands has been prepared. We recently reported the synthesis and application of the novel chiral bis-arsine ligand 2 derived from TML.http://blucherproceedings.com.br/articles/details/2323Fil: Parajón Puenzoa, Sol C. Universidad Nacional de Córdoba. Facultad de Ciencias QuÃmicas. Departamento de QuÃmica Orgánica; Argentina.Fil: Parajón Puenzoa, Sol C. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Investigaciones en FÃsico-quÃmica de Córdoba; Argentina.Fil: Parajón Puenzoa, Sol C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil: Parajón Puenzoa, Sol C. Universidad de Buenos Aires. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro de Investigaciones en Hidratos de Carbonos; Argentina.Fil: Arata Badano, JoaquÃn. Universidad Nacional de Córdoba. Facultad de Ciencias QuÃmicas. Departamento de QuÃmica Orgánica; Argentina.Fil: Arata Badano, JoaquÃn. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Investigaciones en FÃsico-quÃmica de Córdoba; Argentina.Fil: Lopez Vidal, Martin G. Universidad Nacional de Córdoba. Facultad de Ciencias QuÃmicas. Departamento de QuÃmica Orgánica; Argentina.Fil: Lopez Vidal, Martin G. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Investigaciones en FÃsico-quÃmica de Córdoba; Argentina.Fil: Varela, Oscar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil: Varela, Oscar. Universidad de Buenos Aires. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro de Investigaciones en Hidratos de Carbonos; Argentina.Fil: MartÃn, Sandra E. Universidad Nacional de Córdoba. Facultad de Ciencias QuÃmicas. Departamento de QuÃmica Orgánica; Argentina.Fil: MartÃn, Sandra E. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Instituto de Investigaciones en FÃsico-quÃmica de Córdoba; Argentina.QuÃmica Orgánic
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Phenotypic heterogeneity and genetic modification of P102L inherited prion disease in an international series
The largest kindred with inherited prion disease P102L, historically Gerstmann-Sträussler-Scheinker syndrome, originates from central England, with émigrés now resident in various parts of the English-speaking world. We have collected data from 84 patients in the large UK kindred and numerous small unrelated pedigrees to investigate phenotypic heterogeneity and modifying factors. This collection represents by far the largest series of P102L patients so far reported. Microsatellite and genealogical analyses of eight separate European kindreds support multiple distinct mutational events at a cytosine-phosphate diester-guanidine dinucleotide mutation hot spot. All of the smaller P102L kindreds were linked to polymorphic human prion protein gene codon 129M and were not connected by genealogy or microsatellite haplotype background to the large kindred or each other. While many present with classical Gerstmann-Sträussler-Scheinker syndrome, a slowly progressive cerebellar ataxia with later onset cognitive impairment, there is remarkable heterogeneity. A subset of patients present with prominent cognitive and psychiatric features and some have met diagnostic criteria for sporadic Creutzfeldt-Jakob disease. We show that polymorphic human prion protein gene codon 129 modifies age at onset: the earliest eight clinical onsets were all MM homozygotes and overall age at onset was 7 years earlier for MM compared with MV heterozygotes (P = 0.02). Unexpectedly, apolipoprotein E4 carriers have a delayed age of onset by 10 years (P = 0.02). We found a preponderance of female patients compared with males (54 females versus 30 males, P = 0.01), which probably relates to ascertainment bias. However, these modifiers had no impact on a semi-quantitative pathological phenotype in 10 autopsied patients. These data allow an appreciation of the range of clinical phenotype, modern imaging and molecular investigation and should inform genetic counselling of at-risk individuals, with the identification of two genetic modifiers
Dynamical Gauge Symmetry Breaking in Extension of the Standard Model
We study the extension of the Standard model with a
strong U(1) coupling. We argue that current experiments limit this coupling to
be relatively large. The model is dynamically broken to the Standard model at the scale of a few TeV with all the extra gauge bosons
and the exotic quarks acquiring masses much larger than the scale of
electroweak symmetry breaking. Furthermore we find that the model leads to
large dynamical mass of the top quark and hence also breaks the electroweak
gauge symmetry. It therefore leads to large dynamical effects within the
Standard model and can partially replace the Higgs interactions.Comment: 4 pages, revtex, no figures; revised version predicting realistic
mass spectru
Aerosol single scattering albedo dependence on biomass combustion efficiency: Laboratory and field studies
Single scattering albedo (ω) of fresh biomass burning (BB) aerosols produced from 92 controlled laboratory combustion experiments of 20 different woods and grasses was analyzed to determine the factors that control the variability in ω. Results show that ω varies strongly with fire-integrated modified combustion efficiency (MCEFI)—higher MCEFI results in lower ω values and greater spectral dependence of ω. A parameterization of ω as a function of MCEFI for fresh BB aerosols is derived from the laboratory data and is evaluated by field observations from two wildfires. The parameterization suggests that MCEFI explains 60% of the variability in ω, while the 40% unexplained variability could be accounted for by other parameters such as fuel type. Our parameterization provides a promising framework that requires further validation and is amenable for refinements to predict ω with greater confidence, which is critical for estimating the radiative forcing of BB aerosols
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