1,697 research outputs found
Warm Inflation, Neutrinos and Dark matter: a minimal extension of the Standard Model
We show that warm inflation can be realized within a minimal extension of the
Standard Model with three right-handed neutrinos, three complex scalars and a
gauged lepton/B-L U(1) symmetry. This simple model can address all the
shortcomings of the Standard Model that are not related to fine-tuning, within
general relativity, with distinctive experimental signatures that can be probed
in the near future. The inflaton field emerges from the collective breaking of
the U(1) symmetry, and interacts with two of the right-handed neutrinos,
sustaining a high-temperature radiation bath during inflation. The discrete
interchange symmetry of the model protects the scalar potential against large
thermal corrections and leads to a stable inflaton remnant at late times which
can account for dark matter. Consistency of the model and agreement with Cosmic
Microwave Background observations naturally yield light neutrino masses below
0.1 eV, while thermal leptogenesis occurs naturally after a smooth exit from
inflation into the radiation era.Comment: 43 pages (30 main + 13 appendices), 8 figures. Comments are welcom
Restless legs syndrome in patients with high serum ferritin and normal iron levels
Trabajo presentado como póster
en el 18.º Congreso de la European
Sleep Research Society, celebrado
en Innsbruck (Austria) en 2006Objetivo. Documentar la asociación entre síndrome de piernas inquietas (SPI) y concentraciones de ferritina elevadas en
cinco pacientes.
Pacientes y métodos. Estudiamos a cinco varones con una edad media de 59 años (rango: 36-73 años). Todos los pacientes
fueron remitidos por SPI (dos de ellos donantes de sangre), en dos casos asociado a síndrome de apnea obstructiva
del sueño. Se efectuaron registros videopolisomnográficos y se realizó una analítica para determinar los niveles de ferritina
y hierro en plasma.
Resultados. Los cinco pacientes presentaban criterios clínicos de SPI: parestesias en las pantorrillas asociadas a una necesidad
imperiosa de mover las piernas, inquietud motora, agravamiento de los síntomas por la tarde y por la noche,
mejoría con el movimiento, dificultad de conciliación del sueño y despertares nocturnos frecuentes. La exploración neurológica,
el electroencefalograma, el electromiograma y la resonancia magnética cerebral fueron normales. Los registros
videopolisomnográficos mostraron sueño nocturno fragmentado, reducción del tiempo total de sueño, escasa eficiencia,
índice de apnea-hipopnea > 10/h en dos casos, y en los cinco casos, índice de movimientos periódicos de las piernas por
hora de sueño > 5/h. En todos los casos los niveles de hierro sérico estaban dentro de los límites normales y la concentración
de ferritina era elevada.
Conclusiones. La asociación entre SPI con movimientos periódicos de las piernas durante el sueño, hierro sérico normal
y ferritina elevada no se ha descrito previamente. El hallazgo de la disminución de concentración de ferritina en uno de
los pacientes –meses más tarde del tratamiento con fármacos dopaminérgicos– apoya la implicación de un mecanismo
dopaminérgico en la fisiopatología del SPIAim. To document the association between restless legs syndrome (RLS) and high ferritin levels in five patients.
Patients and methods. The five patients were male, mean age: 59 years (range: 36-73 years). The patients were referred
for RLS (two of them blood donors), in two cases associated with obstructive sleep apnea. Patients underwent a video-PSG
recording. Serum iron and serum ferritin were determined.
Results. All patients fulfilled the clinical criteria for RLS: leg paresthesias associated with an urge to move, motor restlessness,
worsening of symptoms during the evening and night, and partial relief with activity, difficulty falling asleep, and
presence of nocturnal awakenings due to RLS. Neurological examination, EEGs, EMGs and MRIs were normal. Video-PSGs
recordings showed a disturbed and fragmented sleep with a reduction in total sleep time, low sleep efficiency, respiratory
abnormalities with an apnea-hipopnea index > 10/h in two cases, and in all of them a periodic leg movements index > 5/h.
The serum iron levels were within the normal range in all cases, whereas those in serum ferritin levels were high.
Conclusions. To our knowledge the association of normal serum iron with high serum ferritin levels in patients diagnosed
clinically and polygraphically as having RLS with periodic leg movements has not been described before. The notion of an
involvement of a dopaminergic mechanism in the pathophysiology of RLS is supported by the decrease in the values of
serum ferritin concentration observed in one patient during follow-up while being treated with dopaminergic agent
Nuevas técnicas de investigación basadas en la observación de la respuesta emocional de los consumidores. Análisis del servicio de despacho a domicilio de alimento de mascotas
Debido a la dudas respecto de posibles diferencias entre lo que declaran consumidores que participan en estudios de mercado y lo que realmente sienten, se realizó un estudio para evaluar el uso de nuevas técnicas de investigación de conducta de los consumidores, aplicada a la percepción de los participantes respecto de un estímulo de marketing, consistente en el logotipo de una empresa de servicios de despacho a domicilio de alimento para mascotas. La técnica evaluada consistió en la observación no obstructiva de la respuesta emocional de consumidores durante la evaluación dicho logotipo, medida en términos de la emoción predominante y la valencia de dicha emoción. El estudio se organizó en tres etapas, en la primera se realizaron cuatro sesiones de Grupo Focales con un total de 32 participantes, organizados en categorías de acuerdo a su edad y Grupo Socioeconómico. Las etapas dos y tres consistieron en una serie de entrevistas individuales, a un grupo de cinco y seis mujeres respectivamente. Los resultados del trabajo sugieren que el uso de la medición y análisis de la respuesta emocional de las personas, provee de información de utilidad, complementaria a la generada por técnicas tradicionales de investigación, contribuyendo de ese modo con información que permite generar estímulos de marketing más coherentes para los consumidores
The elimination of the influence of ambient environmental effects on the structure of `inert\u27 polymers
The construction and use of a vacuum chamber suitable for conventional X-ray diffraction has revealed the influence of the ambient environment, including moisture, on the bulk structure of very thin polymer films. It is concluded that studies of thin film organic systems, even those thought not to be perturbed by ambient water vapor and other contaminants, may benefit from undertaking some studies in such small sample vacuum chambers
The elimination of the influence of ambient environmental effects on the structure of `inert\u27 polymers
The construction and use of a vacuum chamber suitable for conventional X-ray diffraction has revealed the influence of the ambient environment, including moisture, on the bulk structure of very thin polymer films. It is concluded that studies of thin film organic systems, even those thought not to be perturbed by ambient water vapor and other contaminants, may benefit from undertaking some studies in such small sample vacuum chambers
Adsorbate/absorbate interactions with organic ferroelectric polymers
We discuss the interactions of adsorbates with the organic ferroelectric copolymer poly(vinylidene fluoride (PVDF)–trifluoroethylene (TrFE)). Range of molecular adsorbates is discussed from the smaller polar molecules like water, which is small enough to both adsorb and absorb, to the larger macrocyclic metal–organic metal phthalocyanines. The changes in local dipole orientation may affect the strength of the coupling between adsorbate or absorbate and the copolymer poly(vinylidene fluoride–trifluoroethylene). The interface dipole interactions may also affect device properties. The dipole interactions are implicated at the interface between copper phthalocyanine and poly(vinylidene fluoride with trifluoroethylene) affecting the band offsets and the diode properties
Formación en sostenibilidad y su efecto en el comportamiento y la actitud de los estudiantes universitarios
El trabajo se basa en un estudio sobre la formación y el conocimiento de los alumnos
universitarios acerca del concepto sostenibilidad aplicado al turismo, con el fin de
analizar su efecto en el comportamiento y la actitud de los estudiantes cuando viajan.
Se integra en un proyecto internacional más amplio basado en una encuesta on-line, que
en este caso se ha dirigido a los alumnos de la Facultad de Turismo y Finanzas y de la
Facultad de Ciencias Económicas y Empresariales de la Universidad de Sevilla. Los
objetivos del trabajo son los siguientes:
1) Comparar los resultados de los alumnos de Turismo con los de Administración de
Empresas, Economía y Marketing y observar si existen diferencias entre los dos
grupos de estudiantes, tanto en relación con su formación sobre la materia, como
con su comportamiento y actitud frente al turismo sostenible.
2) De existir diferencias, ver en qué medida pudieran derivarse de la formación
recibida y asimismo del contacto con el sector económico sobre el que se analiza
el concepto de sostenibilidad.
Los resultados del trabajo refuerzan nuestra idea inicial de la necesidad de incorporar el
concepto de sostenibilidad en programas y titulaciones universitarias y plantear no solo
conocimientos disciplinares orientados al “saber” y profesionales orientados al “saber
hacer”, sino también actitudes para un compromiso ético orientadas a la protección del
medio ambiente y a la preservación de los pueblos y su cultura.Our paper is focused on a study about the education and knowledge of university
students of the concept of sustainability as applied to tourism with the aim of analysing
its effect on their behaviour and attitudes when travelling. The current study is
integrated in a wider international project based on an on-line survey, that in this case
has been focused on the students of the Faculty of Tourism and Finance and the Faculty
of Economics and Business Studies of the University of Seville. The objectives of the
paper are:
1) To compare the results of the Tourism students with those of the Business
Management, Economics and Marketing students, and to observe if there are
differences between the two groups of students, both in relation to their education
of the material, and also to their behaviour and attitudes towards sustainable
tourism.
2) On the existence of these differences, to determine in what measure they could be
derived from the education received, and likewise from the contact with the
economic sector about which the concept of sustainability is analysed in our study.
The results of the study reinforce our initial idea of the necessity for the incorporation of
the concept of sustainability into the degree syllabus, in which not only should
objectives focused on "to know" and "to know how to do" be considered, but also the
attitudes towards an ethic commitment for the protection of the environment and for the
preservation of the people and their cultures
¿Qué conocen los alumnos universitarios sobre sostenibilidad? Un estudio comparativo en universidades de países diferentes
El trabajo que presentamos se centra en un estudio comparativo sobre lo que conocen
los alumnos universitarios acerca del concepto sostenibilidad. El estudio empírico, aún
en curso, se basa en una encuesta on-line dirigida a alumnos de la New York University,
de la Pace University y de la Universidad de Sevilla. Los resultados preliminares
obtenidos nos llevan a justificar la necesaria enseñanza de dicha materia en distintos
cursos y titulaciones universitarias con el fin de difundir una cultura a favor de la
sostenibilidad. Y de ese modo contribuir también a garantizar el desarrollo de las
generaciones futuras y a dar respuesta, asimismo, a la demanda de acciones que
reclaman los organismos internacionales con objeto desarrollar el turismo de una
manera sostenible.Our paper is focused on a comparative study about university’ students knowledge of
sustainability. The ongoing empirical study is based on a survey that has been
administered through online survey platform to a listserv of students from New York
University, Pace University and Universidad de Sevilla. The preliminary results
encourage us to justify the need of teaching about sustainability in different courses at
university degrees in order to spread a pro-sustainability culture and contribute to
guarantee the future generation development. In the same way, this project gives a response to the demanded actions that the international organizations are claiming in
order to develop the tourism in a sustainable way
Analysis of the essential literature on project management in Spanish
The advancement of science and engineering projects is brewing major changes in the various phases of a project. These changes have produced more rigorous aspects of project management that tracks the research fronts of engineering and project management becomes key. However, research in engineering and project management in Spanish is hindered by access to information to enable the person concerned to ascertain the most recent and current research, limiting the exchange of information and strengthening research networks in this field interest with great implications in business, industry and scientific issues. Therefore, the article aims to present the state of the art of engineering research and project management in Spanish, using the analysis of scientific domains and network analysis of the research literature to identify and analyze relationships between authors and documents that establish the base and research fronts topic under study. The results also provide statistics on the contribution of international research in Spanish and scientific collaboration networks
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