8,405 research outputs found
Feasibility of observer system for determining orientation of balloon borne observational platforms
An observer model for predicting the orientation of balloon borne research platforms was developed. The model was employed in conjunction with data from the LACATE mission in order to determine the platform orientation as a function of time
Measurements of partial branching fractions for B → Xulν and determination of |Vub| at BaBar
We present partial branching fractions for inclusive charmless semileptonic B decays B → Xulν, and the determination of the CKM matrix element |Vub|. The analysis is based on a sample of 467 million Υ(4S) decays into B B
pairs collected with the BaBar detector at the PEPII e+e−
storage rings. The invariant mass of the hadronic system, MX, the squared invariant mass of the lepton pair, q2, and the variable P+ = EX − |PX| and their combinations, in the process B → Xulν are used as discriminant variables to suppress semileptonic decays with charm. Partial branching fractions are measured as a function of the cuts on the above variables. Theoretical calculations are used to compute acceptances and related uncertainties, thereby allowing to extract |Vub|
Global analysis of muon decay measurements
We have performed a global analysis of muon decay measurements to establish
model-independent limits on the space-time structure of the muon decay matrix
element. We find limits on the scalar, vector and tensor coupling of right- and
left-handed muons to right- and left-handed electrons. The limits on those
terms that involve the decay of right-handed muons to left-handed electrons are
more restrictive than in previous global analyses, while the limits on the
other non-standard model interactions are comparable. The value of the Michel
parameter eta found in the global analysis is -0.0036 \pm 0.0069, slightly more
precise than the value found in a more restrictive analysis of a recent
measurement. This has implications for the Fermi coupling constant G_F.Comment: 5 pages, 3 table
Branching ratios for the beta decay of 21Na
We have measured the beta-decay branching ratio for the transition from 21Na
to the first excited state of 21Ne. A recently published test of the standard
model, which was based on a measurement of the beta-nu correlation in the decay
of 21Na, depended on this branching ratio. However, until now only relatively
imprecise (and, in some cases, contradictory) values existed for it. Our new
result, 4.74(4)%, reduces but does not remove the reported discrepancy with the
standard model.Comment: Revtex4, 2 fig
Efecto del agregado de alúmina en la calidad del material de aleación de Zinc NÃquel. Adsorción de la alúmina en las partÃculas que ermiten una mayor transferencia de materia al cátodo
En las aleaciones de Zn-Ni es importante un alto contenido de Ni porque aumenta la resistencia del material contra la corrosión. En este sentido, se encontró que la adición de concentraciones mayores de partÃculas de alúmina a la solución de electrólisis, hace que las mismas se incorporen al recubrimiento y aumente la composición de Ni y la microdureza. La adsorción se estudió por VoltametrÃa mediante electrodo gotero de mercurio para explicar por la adsorción, porque mayores concentraciones de partÃculas aumentan la concentración de NÃquel en la aleación. Se estudiaron las texturas en muestras preparadas a espesores crecientes, y su relación con la resistencia a la corrosión. El principal aporte de éste trabajo es que el material del recubrimiento con alúmina, modifica las texturas con espesores crecientes. El espesor óptimo en el que aumenta la textura disminuye la corriente de corrosión, a la vez que a 8Adm-2 el contenido de Ni es de 15 % y la dureza es alta para ZnNi de 350 Vickers, que está ligada al desgaste.Fil:Mahmud, Z. Instituto Nacional de TecnologÃa Industrial (INTI). Procesos SuperficialesFil:Pina, J. Instituto Nacional de TecnologÃa Industrial (INTI). Procesos SuperficialesFil:Gagliardi, J. Instituto Nacional de TecnologÃa Industrial (INTI). Procesos SuperficialesFil:MÃngolo, N. Comisión Nacional de EnergÃa Atómica (CNEA)Fil:Túlio, P. Universidade Tecnológica Federal do Paraná (UTFPR)Fil:Gordillo, G. Universidad de Buenos Aires (UBA). Facultad de Ciencias Exactas y Naturales. Departamento de QuÃmica Inorgánica, AnalÃtica y QuÃmica FÃsic
Spectral-function determination of complex electroweak amplitudes with lattice QCD
We present a novel method to determine on the lattice both the real and imaginary parts of complex electroweak amplitudes involving two external currents and a single hadron or the QCD vacuum in the external states. The method is based on the spectral representation of the relevant time-dependent correlation functions and, by extending the range of applicability of other recent proposals built on the same techniques, overcomes the difficulties related to the analytic continuation from Minkowskian to Euclidean time, arising when intermediate states with energies smaller than the external states contribute to the amplitude. In its simplest form, the method relies on the standard iϵ prescription to regularize the Feynman integrals and at finite ϵ it requires to verify the condition 1/L≪ϵ≪Δ(E), where L is the spatial extent of the lattice and, for any given energy E, Δ(E) represents the typical size of the interval around E in which the hadronic amplitude is significantly varying. In order to illustrate the effectiveness of this approach in a realistic case, we apply the method to evaluate nonperturbatively the hadronic amplitude contributing to the radiative leptonic decay Ds→ℓνℓγ*, working for simplicity with a single lattice ensemble at fixed volume and lattice spacing
Prevention of clostridium difficile infection and associated diarrhea: An unsolved problem
For many years, it has been known that Clostridium difficile (CD) is the primary cause of health-care-associated infectious diarrhea, afflicting approximately 1% of hospitalized patients. CD may be simply carried or lead to a mild disease, but in a relevant number of patients, it can cause a very severe, potentially fatal, disease. In this narrative review, the present possibilities of CD infection (CDI) prevention will be discussed. Interventions usually recommended for infection control and prevention can be effective in reducing CDI incidence. However, in order to overcome limitations of these measures and reduce the risk of new CDI episodes, novel strategies have been developed. As most of the cases of CDI follow antibiotic use, attempts to rationalize antibiotic prescriptions have been implemented. Moreover, to reconstitute normal gut microbiota composition and suppress CD colonization in patients given antimicrobial drugs, administration of probiotics has been suggested. Finally, active and passive immunization has been studied. Vaccines containing inactivated CD toxins or components of CD spores have been studied. Passive immunization with monoclonal antibodies against CD toxins or the administration of hyperimmune whey derived from colostrum or breast milk from immunized cows has been tried. However, most advanced methods have significant limitations as they cannot prevent colonization and development of primary CDI. Only the availability of vaccines able to face these problems can allow a resolutive approach to the total burden due to this pathogen
Perceptions and attitudes toward blue energy and technologies in the Mediterranean area: ASKYOURCITIZENSONBE
An energy transition is needed in order to meet the European pledge of reaching climate neutrality by 2050. This transition cannot ignore the renewable resources available from 70% of the Earth (namely, the oceans and seas). This concept is fundamental for the planet, especially for the Mediterranean area. Marine renewable energies are still under-deployed in the Mediterranean area for many reasons, including legislative constraints, lower energy availability, and technological readiness. An appropriate participatory process including all actors (e.g., policymakers, firms, citizens, and researchers) is necessary for a correct path toward decarbonization. The BLUE DEAL project was conceived and implemented by 12 Mediterranean partners to tackle these issues and set the route for blue energy deployment in the Mediterranean area. Activities already conducted include a survey to probe the perceptions and attitudes of citizens toward blue energy. The survey targeted about 3,000 persons in 12 Mediterranean sites with the aim of bringing citizens into the discussion on future technologies. The results showed that although blue energy is still relatively unknown to the general public (only 42% of respondents were aware of these technologies), there was a general willingness (70%) to host one or more such installations in their areas. Here, we describe our survey method and some empirical results with suggestions for replicability and recommendations on how to use it for policymaking purposes
An instrument for the characterization and calibration of optical sensors
This paper presents the development of a hardware/software system for the characterization of the electronic response of optical (camera) sensors such as matrix and linear color and monochrome Charge Coupled Device (CCD) or Complementary Metal Oxide Semiconductor (CMOS). The electronic response of a sensor is required for inspection purposes. It also allows the design and calibration of the integrating device to achieve the desired performance. The proposed instrument equipment fulfills the most recent European Machine Vision Association (EMVA) 1288 standard ver. 3.1: The spatial non uniformity of the illumination ΔE must be under 3%, and the sensor must achieve an f-number of 8.0 concerning the light source. The following main innovations have achieved this: An Ulbricht sphere providing a uniform light distribution (irradiation) of 99.54%; an innovative illuminator with proper positioning of color Light Emitting Diodes (LEDs) and control electronics; and a flexible C# program to analyze the sensor parameters, namely Quantum Efficiency, Overall System Gain, Temporal Dark Noise, Dark Signal Non Uniformity (DSNU1288), Photo Response Non-Uniformity (PRNU1288), Maximum achievable Signal to Noise Ratio (SNRmax), Absolute sensitivity threshold, Saturation Capacity, Dynamic Range, and Dark Current. This new instrument has allowed a camera manufacturer to design, integrate, and inspect numerous devices and camera models (Necta, Celera, and Aria)
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