Seeding of supercooled polyethylene with extended chain crystals

Seeding of supercooled polyethylene with extended chain crystal

A Review of the Principles and Benefits of Cue-Based Feeding

Literature reflects that neonatal clinical practices are increasingly infant-driven, and promote, developmentally based care. Particularly, in the area of oral feeding, practitioners are moving away from traditional gestational age criteria for the initiation of oral feeding, or progressing feedings based on volume, instead they are trending toward feeding protocols that are based on developmental maturity. A statement released by the American Academy of Pediatrics (2008), made the attainment of independent oral feeding one of the critical criteria for hospital discharge of preterm infants. This statement not only reflected the increased research attention on oral feeding acquisition and outcomes, it caused neonatal clinicians to seriously reconsider their methods for feeding premature infants, so that premature infants could safely acquire oral feeding prior to going home. This paper reviews and summarizes the principles and benefits of cue-based feeding that have been presented in the literature. Cue-based feeding is an outgrowth of developmentally-based care. Being increasingly used in feeding plans for premature infants, cue-based feeding is a feeding method, where, the infant directs how and when it will eat, by displaying behavioral cues and eating reflexes

Interference effects in two-photon ATI by multiple orders high harmonics with random or locked phases

We numerically study 2-photon processes using a set of harmonics from a Ti:Sapphire laser and in particular interference effects in the Above Threshold Ionization spectra. We compare the situation where the harmonic phases are assumed locked to the case where they have a random distribution. Suggestions for possible experiments, using realistic parameters are discussed.Comment: 11 pages, 13 figures, LaTe

Coulomb-Volkov approach of ionization by extreme ultraviolet laser pulses in the subfemtosecond regime

In conditions where the interaction betweeen an atom and a short high-frequency extreme ultraviolet laser pulse is a perturbation, we show that a simple theoretical approach, based on Coulomb-Volkov-type states, can make reliable predictions for ionization. To avoid any additional approximation, we consider here a standard case : the ionization of hydrogen atoms initially in their ground state. For any field parameter, we show that the method provides accurate energy spectra of ejected electrons, including many above threshold ionization peaks, as long as the two following conditions are simultaneously fulfilled : (i) the photon energy is greater than or equal to the ionization potential ; (ii) the ionization process is not saturated. Thus, ionization of atoms or molecules by the high order harmonic laser pulses which are generated at present may be addressed through this Coulomb-Volkov treatment.Comment: 19 pages including 5 figures and figure caption

Sociolinguistic variation in the nativisation of BSL fingerspelling

British Sign Language (BSL) is a visual-gestural language distinct from spoken languages used in the United Kingdom but in contact with them. One product of this contact is the use of fingerspelling to represent English words via their orthography. Fingerspelled loans can become “nativised”, adapting manual production to conform more closely to the native lexicon’s inventory of phonemic constraints. Much of the previous literature on fingerspelling has focused on one-handed systems but, unlike the majority of sign languages, BSL uses a two-handed manual alphabet. What is the nature of nativisation in BSL, and does it exhibit sociolinguistic variation? We apply a cross-linguistic model of nativisation to BSL Corpus conversation and narrative data (http://bslcorpusproject.org) obtained from 150 signers in 6 UK regions. Mixed effects modelling is employed to determine the influence of social factors. Results show that the participants’ home region is the most significant factor, with London and Birmingham signers significantly favouring use of fully nativised fingerspelled forms. Non-nativised sequences are significantly favoured in signers of increasing age in Glasgow and Belfast. Gender and parental language background are not found to be significant factors in nativisation. The findings also suggest a form of reduction specific to London and Birmingham

Speeding up simulations of relativistic systems using an optimal boosted frame

It can be computationally advantageous to perform computer simulations in a Lorentz boosted frame for a certain class of systems. However, even if the computer model relies on a covariant set of equations, it has been pointed out that algorithmic difficulties related to discretization errors may have to be overcome in order to take full advantage of the potential speedup. We summarize the findings, the difficulties and their solutions, and show that the technique enables simulations important to several areas of accelerator physics that are otherwise problematic, including self-consistent modeling in three-dimensions of laser wakefield accelerator stages at energies of 10 GeV and above.Comment: To be published in the proceedings of DPF-2009, Detroit, MI, July 2009, eConf C09072

Performance disclosure on the web, an exploration of the impact of managers' perceptions of stakeholder concerns

Using an exploratory research perspective, we examine how multinational firms' executives' motivations map into corporate website performance disclosure. Our focus is on managements' beliefs about the relevance of financial, social and environmental performance disclosures and how these beliefs relate to the firms' website disclosure practices. For 56 companies, we use managers' perceptions along with data captured from websites. Employing factor and regression analysis, we find that executives' perceptions of stakeholders' importance affect their firms' web-based disclosure practices and foci. Additionally, strategic focus, media, size of organization, profitability, leverage and analyst following are found influential in explaining types of performance disclosures made.Usando una perspectiva de investigación exploratoria, examinamos cómo las motivaciones de los ejecutivos de empresas multinacionales se esquematizan en la revelación del desempeño de las páginas web corporativas. Nuestro enfoque está en las creencias de dirección sobre la relevancia de la revelación del desempeño financiero, social y ambiental, y cómo estas creencias están relacionadas con las prácticas de divulgación del sitio web de la firma. Para 56 compañías, usamos percepciones de directores junto con la información conseguida de páginas webs. Empleando el análisis de factores y de regresión, encontramos que estas percepciones sobre la importancia de los inversores afecta a sus prácticas de divulgación en las páginas webs de la firma, y a sus focos de atención. Además, el enfoque estratégico, los medios de comunicación, el tamaño de la organización, la rentabilidad, la influencia y los analistas financieros siguientes influyen en la explicación de los tipos de divulgaciones de desempeño

Dynamics of coupled bosonic systems with applications to preheating

Coupled, multi-field models of inflation can provide several attractive features unavailable in the case of a single inflaton field. These models have a rich dynamical structure resulting from the interaction of the fields and their associated fluctuations. We present a formalism to study the nonequilibrium dynamics of coupled scalar fields. This formalism solves the problem of renormalizing interacting models in a transparent way using dimensional regularization. The evolution is generated by a renormalized effective Lagrangian which incorporates the dynamics of the mean fields and their associated fluctuations at one-loop order. We apply our method to two problems of physical interest: (i) a simple two-field model which exemplifies applications to reheating in inflation, and (ii) a supersymmetric hybrid inflation model. This second case is interesting because inflation terminates via a smooth phase transition which gives rise to a spinodal instability in one of the fields. We study the evolution of the zero mode of the fields and the energy density transfer to the fluctuations from the mean fields. We conclude that back reaction effects can be significant over a wide parameter range. In particular for the supersymmetric hybrid model we find that particle production can be suppressed due to these effects.Comment: 23 pages, 16 eps-figures, minor changes in the text, references added, accepted for publication in PR