10,984 research outputs found
Top-Quark Production and Decay in the MSSM
We review the features of top-quark decays and loop-induced effects in the
production cross section and CP-violating observables of e+e- -> t t-bar which
are specific to the R-parity conserving Minimal Supersymmetric Standard Model
(MSSM).Comment: LaTeX, 28 pages, 10 figures included, uses cite.sty. Contribution to
the proceedings of the 2nd Joint ECFA/DESY Workshop on Physics and Detectors
for a Linear Electron-Positron Collider. References adde
Análisis bibliométrico de las publicaciones científicas españolas en la categoría Construction & Building Technology de la base de datos Web of Science (1997-2008)
En este trabajo se analizan las publicaciones procedentes de instituciones españolas recogidas en las revistas de la categoría Construction & Building Technology de la base de datos Web of Science para el periodo 1997-2008. El número de revistas incluidas es de 35 y el número de artículos publicados ha sido de 760 (Article o Review). Se ha realizado una evaluación bibliométrica con dos nuevos parámetros: Factor de Impacto Ponderado y Factor de Impacto Relativo; asimismo se incluyen el número de citas y el número de documentos a nivel institucional. Entre los centros con una mayor producción científica destaca, como era de prever, el Instituto de Ciencias de la Construcción Eduardo Torroja (CSIC), mientras que atendiendo al Factor de Impacto Ponderado ocupa el primer lugar la Universidad de Vigo. Por otro lado, sólo dos revistas Cement and Concrete Research y Materiales de Construcción aglutinan el 45.26% de toda la producción científica española, con 172 trabajos cada una de ellas. En cuanto a la colaboración internacional, destacan países como Inglaterra, México, Estados Unidos, Italia, Argentina y Franci
Equal and unequal profit sharing in highly interdependent work groups: a laboratory experiment
We study behavior in a simplified representation of an organization with high task interdependence. The production process involves three stages such that output of earlier stages is the necessary input for subsequent stages. Work at earlier stages is easier than at later stages and the product is only final if it goes successfully through the highest stage. We compare the effects on the performance of the organization of a payment scheme in which profits are equally shared by all those involved in the production process with one where the participation in profits is strongly increasing in the production stage. The comparison is made for two ways of assigning individuals to the production stage: randomly or by merit. We find that initially there is no difference in the organization’s profit between the two sharing schemes, but over time profits increase more with the equal sharing scheme. Changes in profits over time can be explained by changes in production performance over time. After participants have gained experience in the tasks, the equal profit sharing scheme has positive performance effects both at the lowest and the highest production stages. There are only minor differences in the results depending on whether the payment scheme is exogenously imposed or chosen by the person at the highest stage
Distributional concerns in managers’ compensation schemes for heterogeneous workers: experimental evidence
We present results from three-player experiments aimed at studying distributional concerns in how ownermanagers compensate themselves and workers of different productivities and effort costs, as well as their relations to various equity principles. We are also interested in how owner-managers decisions’ are affected by pay secrecy. We use a game in which workers first exert effort and owner-managers then decide on bonuses for themselves and workers. Our design includes four treatments: 1) different productivities of workers with complete information; 2) different productivities of workers with pay secrecy among workers; 3) different effort cost of workers with complete information; and 4) different effort cost of workers with pay secrecy among workers. The equity principles we focus on are ‘production-equity’, higher production leads to higher wage, and ‘effort-cost equity’, higher effort-cost leads to higher wage. Our results show that, on average, managers do not pay relative wages in accordance to relative production levels, but also take effort-cost into account. Pay secrecy affects compensation differences among workers in a limited way. Across all treatments about 50% of all manager choices are compatible both with ‘production equity’ and with ‘effort- cost equity’, about 20% only with production equity and about 15% only with effort-cost equity
Application of Deep Compaction Techniques to Liquefaction Prevention
This article analyzes the application of dynamic compaction, vibroflotation and vibroreplacement (stone columns) to liquefaction prevention. The ground types to which they can be applied, the depths that can be reached and the degree of improvement that can be obtained are all studied. Finally, and on the basis of the above, basic guidelines are given for the design of ground improvement with these techniques and for the aforementioned purpose
Outdoor testing of the photoprotection provided by a new water-based broad-spectrum SPF50+ sunscreen product: Two double-blind, split-face, randomized controlled studies in healthy adults
Purpose: Users often under-apply sunscreens, and one of the main reasons cited for this is the cosmetic formulation of the product. To address this, we developed a water-based sunscreen. The product underwent standard laboratory testing (ISO 24444: 2010) and was determined as sun protection factor (SPF) 50+. However, such laboratory testing does not take into account environmental factors of in-use conditions that could potentially affect sunscreen efficacy, particularly of new cosmetic formulations. We aimed to test this product in conditions more representative of real-life solar exposure, to confirm its reported laboratory efficacy.
Methods: Two double-blind, randomized, controlled, split-face intra-individual studies were conducted during summer months in Barcelona. One study compared the product against an SPF15 control (reference standard P3 of ISO 24444: 2010), while the other compared against an SPF50+ control (another commercially available sunscreen). A technician applied the products before sun exposure: investigational product (IP) to one half of the face and the respective control product to the other. Subjects spent 4–6 hrs outdoors performing quiet activities, and sunscreens were reapplied at 2 hourly intervals. A dermatologist clinically scored facial erythema at baseline and at 24 hrs.
Results: Sixty-five subjects were included in total. In both studies, skin treated with the IP showed no significant increase in clinical erythema scoring at 24 hrs. There were statistically significant differences between the IP and the SPF15, but not between the IP and the SPF50+ control. SPF15 did not protect all subjects against solar-induced erythema.
Conclusion: These outdoor studies confirm the efficacy of this new SPF50+ water-based sunscreen in conditions that closer represent real-life sun exposure
Continuous spectra in high-harmonic generation driven by multicycle laser pulses
We present observations of the emission of XUV continua in the 20-37 eV
region by high harmonic generation (HHG) with - pulses
focused onto a Kr gas jet. The underlying mechanism relies on coherent control
of the relative delays and phases between individually generated attosecond
pulse, achievable by adjusting the chirp of the driving pulses and the
interaction geometry. Under adequate negative chirp and phase matching
conditions, the resulting interpulse interference yields a continuum XUV
spectrum, which is due to both microscopic and macroscopic (propagation)
contributions. This technique opens the route for modifying the phase of
individual attosecond pulses and for the coherent synthesis of XUV continua
from multicycle driving laser pulses without the need of an isolated attosecond
burst.Comment: 14 pages, 5 figures. Submitted to Physical Review
Drug Abuse Prevention Campaigns in Chile (2004-2014): Between Prohibitionism and Stigmatisation
This paper studies the presence and reproduction of the ‘prohibitionist’ paradigm in the Chilean state’s drug policy by studying its drug abuse prevention campaigns. By means of a content analysis of the television spots broadcast between 2004 and 2014, the discursive and ideological elements present in these campaigns were examined. First and foremost, the results show that, despite institutional change and the creation of bodies such as the National Service for the Prevention and Rehabilitation of Drug and Alcohol Use (SENDA) and the National Council for Narcotics Control (CONACE), the state’s discourse has remained focused on the prohibitionist paradigm, resorting to highly stereotyped emotional messages. Secondly, drug consumption has been stigmatised and framed in profoundly dramatic contexts in which users belong to the criminal underworld or have physical and/or cognitive impairments. Thirdly, notwithstanding the fact that there are certain differences between the communication approaches employed by the SENDA and the CONACE, the discourses of both institutions are very uniform and reductionist. In order to design more efficient media campaigns, target audiences should be encouraged to analyse and ponder reflectively on the issue by conveying rational messages that contrast facts and data and offer a positive vision stressing the benefits of a healthy lifestyle.Este artículo cuestiona la presencia y reproducción del paradigma “prohibicionista” en la política de drogas del Estado chileno, a través del estudio de sus campañas de comunicación para la prevención del consumo de drogas. Mediante un análisis de contenido de los spots televisivos aparecidos entre 2004-2014 se estudiaron los elementos discursivos e ideológicos presentes en las campañas. Los resultados mostraron primero que, pese al cambio institucional y la creación de organismos como SENDA y CONACE, los contenidos elaborados y reproducidos por el discurso estatal se han mantenido enfocados en el paradigma prohibicionista recurriendo a mensajes emocionales, muy estereotipados. Segundo, que el usuario de drogas está estigmatizado y se sitúa en contextos con fuerte carga dramática donde los consumidores pertenecen al ámbito criminal o al de la discapacidad intelectual. Tercero, que a pesar de que existen ciertas diferencias en el tratamiento comunicacional entre SENDA y CONACE, ambas instituciones mantienen un discurso muy homogéneo y reduccionista. Para lograr una mejor eficiencia de las campañas mediáticas, por el contrario, debería inducirse al receptor a realizar un análisis y reflexión crítica en torno al tema y mostrar mensajes racionales que contrasten hechos y datos y ofrezcan una visión positiva que refuerce los beneficios de un estilo de vida saludable
Optimization of a Slurry Dispersion Method for Minerals and Trace Elements Analysis in Infant Formulae by ICP OES and FAAS
Infant formula developed by manufacturers requires a rigorous control of composition,
particularly those elements added routinely in an attempt to mimic the mineral
composition of human milk. A total of 97 different types of powdered infant formulae
(preterm, adapted starter, adapted follow-up, toddler, specialised and soy based
formulae) commercially available in Spain were studied. It is noteworthy great
differences in mineral (Ca, P, Mg) and trace element (Zn, Fe, Cu, Mn) contents found
between analysed and listed in label information. The development of a fast, simple and
direct slurry method for the determination of these essential micronutrients in infant
formula by inductively coupled plasma optical emission spectrometry (ICP OES) and
flame atomic absorption spectrometry (FAAS) was performed in order to help in quality
control tasks. Infant formula samples were solubilised using different amounts of
several different solvents. An addition of 250 L of a solution 10 %
tetramethylammonium hydroxide and 25 % ammonium hydroxide were required for the
accurate quantification of Ca and P, Mg, Zn, Fe, Cu and Mn, respectively. The standard
reference material 1549 non-fat milk powder was solubilised to compare the validity of
assayed methodology following slurry nebulisation and traditional microwave-assisted
acid digestion method. Good agreement of the analytical results by both ICP OES and
FAAS, with the certified values was obtained. Method performance parameters
(accuracy, precision and methodological detection limits) were determined for studied
elements to check the quality and usefulness of the optimised slurry method. The
analytical procedure was applied successfully to the analysis of a representative group
of infant formulae. Levels of analysed elements were graphically represented, showing
an acceptable comparability between slurry and acid-mineralisation method set by linear
correlation coefficients and slopes close to the unit. The described simple and slurry
method is appropriate, as an attractive alternative, for routine control analysis of added
essential elements in infant formulae regardless of predominant protein type used in
manufacture
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