1,486 research outputs found
The unbinding transition of mixed fluid membranes
A phenomenological model for the unbinding transition of multi-component
fluid membranes is proposed, where the unbinding transition is described using
a theory analogous to Flory-Huggins theory for polymers. The coupling between
the lateral phase separation of inclusion molecules and the membrane-substrate
distance explains the phase coexistence between two unbound phases as observed
in recent experiments by Marx et al. [Phys. Rev. Lett. 88, 138102 (2002)].
Bellow a critical end-point temperature, we find that the unbinding transition
becomes first-order for multi-component membranes.Comment: 7 pages, 3 eps figure
Factors affecting the vaccination choices of pregnant women for their children. A systematic review of the literature
In recent years, an increase in vaccine hesitancy has led to a decrease in vaccination coverage in several countries. We conducted a systematic review of studies that assessed knowledge of and attitudes toward pediatric vaccinations, and the vaccination choices and their determinants among pregnant women. A total of 6,277 records were retrieved, and 16 full texts were included in the narrative synthesis. The published literature on the topic shows that, overall, pregnant women believe that vaccines are important for the protection of their children and the community, but various concerns and misunderstandings persist around vaccine safety and efficacy, which reduce the trust of expectant mothers in immunization. Nevertheless, such attitudes and choices vary depending on the vaccine being considered and the corresponding determinants should therefore be studied in the context of each specific vaccination. Further research on this topic is needed, particularly in non-western countries
CP violation in scatterings, three body processes and the Boltzmann equations for leptogenesis
We obtain the Boltzmann equations for leptogenesis including decay and
scattering processes with two and three body initial or final states. We
present an explicit computation of the CP violating scattering asymmetries. We
analyze their possible impact in leptogenesis, and we discuss the validity of
their approximate expressions in terms of the decay asymmetry. In scenarios in
which the initial heavy neutrino density vanishes, the inclusion of CP
asymmetries in scatterings can enforce a cancellation between the lepton
asymmetry generated at early times and the asymmetry produced at later times.
We argue that a sizeable amount of washout is crucial for spoiling this
cancellation, and we show that in the regimes in which the washouts are
particularly weak, the inclusion of CP violation in scatterings yields a
reduction in the final value of the lepton asymmetry. In the strong washout
regimes the inclusion of CP violation in scatterings still leads to a
significant enhancement of the lepton asymmetry at high temperatures; however,
due to the independence from the early conditions that is characteristic of
these regimes, the final value of the lepton asymmetry remains approximately
unchanged.Comment: 24 pages, 6 figures. One appendix added. Some numerical results and
corresponding figures (mainly fig. 3) corrected. Final version to be
published in JHE
Does e-learning policy drive change in Higher Education?: A case study relating models of organisational change to e-learning implementation
Due to the heightened competition introduced by the potential global market and the need for structural changes within organisations delivering e-content, e-learning policy is beginning to take on a more significant role within the context of educational policy per se. For this reason, it is becoming increasingly important to establish what effect such policies have and how they are achieved. This paper addresses this question, illustrating five ways in which change is understood (Fordist, evolutionary, ecological, community of practice and discourse-oriented) and then using this range of perspectives to explore how e-learning policy drives change (both organisational and pedagogic) within a selected higher education institution. The implications of this case are then discussed, and both methodological and pragmatic conclusions are drawn, considering the relative insights offered by the models and ways in which change around e-learning might be supported or promoted
Validation of the self-management ability scale (SMAS) and development and validation of a shorter scale (SMAS-S) among older patients shortly after hospitalisation
Background: The 30-item Self-Management Ability Scale (SMAS) measures self-management abilities (SMA). Objectives of this study were to (1) validate the SMAS among older people shortly after hospitalisation and (2) shorten the SMAS while maintaining adequate validity and reliability. Methods: Our study was conducted among older individuals (>= 65) who had recently been discharged from a hospital. Three months after hospital admission, 296/456 patients (65% response) were interviewed in their homes. We tested the instrument by means of structural equation modelling, and examined its validity and reliability. In addition, we tested internal consistency of the SMAS and SMAS-S among a study sample of patients at risk for cardiovascular diseases. Results: After eliminating 12 items, the confirmatory factor analyses revealed good indices of fit with the resulting 18-item SMAS (SMAS-S). To estimate construct validity of the instrument, we looked at correlations between SMAS subscale scores and overall well-being scores as measured by Social Product Function (SPF-IL) and Cantril's ladder. All SMAS subscales of the original and short version significantly correlated with SPF-IL scores (all at p <= 0.001) and Cantril's ladder (for the cognitive well-being subscale p <= 0.01; all other subscales at p <= 0.001). The findings indicated validity. Analyses of the SMAS and SMAS-S in the sample of patients at risk for cardiovascular diseases showed that both instruments are reliable. Conclusions: The psychometric properties of both the SMAS and SMAS-S are good. The SMAS-S is a promising alternate instrument to evaluate self-management abilities
A Two-Phase ASP Encoding for Solving Rehabilitation Scheduling
The rehabilitation scheduling process consists of planning rehabilitation physiotherapy sessions for patients, by assigning proper operators to them in a certain time slot of a given day, taking into account several requirements and optimizations, e.g., patientâs preferences and operatorâs work balancing. Being able to efficiently solve such problem is of upmost importance, in particular after the COVID-19 pandemic that significantly increased rehabilitationâs needs. In this paper, we present a solution to rehabilitation scheduling based on Answer Set Programming (ASP), which proved to be an effective tool for solving practical scheduling problems. Results of experiments performed on both synthetic and real benchmarks, the latter provided by ICS Maugeri, show the effectiveness of our solution
The relations between research in Science teaching and teacher education: representations
This study was conducted with the objective of investigating representations of researchers from the area of the teaching of Physics about the possible influence of the research in the area of Science teaching upon the way in which teachers are educated in Brazil. For that, an analysis was made of the answers to a question formulated in interviews made with 13 researchers from the field of the teaching of Physics, which were indicated by their peers through an electronic mail sent to researchers in Science teaching, including the subareas of Biology, Physics, Geosciences and Chemistry. The discourse analysis developed in France by Michel PĂȘcheux, based on elements obtained mainly from publications by Eni Orlandi in Brazil, gave the theoretical support to the study. The representations that the selected discourses allowed to infer suggest that the above-mentioned influence is small. However, factors of great import were mentioned, including factors internal to the area, as well as factors associated to public policies. A wide diversity of positions among the researchers interviewed could also be observed. On the whole, the factors mentioned by the interviewees constitute a wide configuration scenario of representations that can be an element for reflection to other researchers. We believe that these representations have the potential to contribute to the appearance of effective influences in the form of the development of public policies, without the need for prescriptions and with fewer and fewer empty recommendations.Este estudo foi realizado com o objetivo de investigar representaçÔes de pesquisadores da ĂĄrea de ensino de FĂsica sobre a possĂvel interferĂȘncia da pesquisa da ĂĄrea de ensino de CiĂȘncias na maneira como se formam professores no Brasil. Para tal, foram analisadas as respostas a uma questĂŁo formulada em entrevistas a treze pesquisadores do ensino da FĂsica, indicados por seus pares por meio de correio eletrĂŽnico encaminhado a pesquisadores do ensino de CiĂȘncias, incluindo as subĂĄreas de Biologia, FĂsica, GeociĂȘncias e QuĂmica. A anĂĄlise de discurso desenvolvida na França por Michel PĂȘcheux, a partir de subsĂdios obtidos principalmente em publicaçÔes de Eni Orlandi no Brasil, foi o apoio teĂłrico que sustentou o estudo. As representaçÔes que os discursos selecionados permitem inferir evidenciam pequena influĂȘncia. Entretanto, foram enunciados fatores de grande abrangĂȘncia, incluindo desde aqueles internos Ă prĂłpria ĂĄrea, quanto fatores associados a polĂticas pĂșblicas. TambĂ©m se observou uma diversidade de posiçÔes entre os pesquisadores entrevistados. No conjunto, os fatores abordados pelos entrevistados constituem um amplo quadro configurativo de representaçÔes que pode ser elemento de reflexĂŁo para outros pesquisadores. Acreditamos que essas representaçÔes tĂȘm potencial de contribuição para efetivas interferĂȘncias na forma de realização de polĂticas pĂșblicas, sem a necessidade do uso de prescriçÔes e cada vez menos com recomendaçÔes vazias.33534
- âŠ