451 research outputs found
On the nature of Bose-Einstein condensation enhanced by localization
In a previous paper we established that for the perfect Bose gas and the
mean-field Bose gas with an external random or weak potential, whenever there
is generalized Bose-Einstein condensation in the eigenstates of the single
particle Hamiltonian, there is also generalized condensation in the kinetic
energy states. In these cases Bose-Einstein condensation is produced or
enhanced by the external potential. In the present paper we establish a
criterion for the absence of condensation in single kinetic energy states and
prove that this criterion is satisfied for a class of random potentials and
weak potentials. This means that the condensate is spread over an infinite
number of states with low kinetic energy without any of them being
macroscopically occupied
Literature Review Sonnet
This poem is a sonnet that is modeled after Shakespeare\u27s Sonnet 18 and demonstrates appreciation for the literature review stage of the research process
Supporting Safety Culture in Academia: Giving a Voice to Faculty
In the words of Sir Winston Churchill, “The difference between mere management and true leadership is communication.” Department leaders have a vital role to play at all institutional levels when it comes to achieving an optimal safety culture that promotes safety voice behavior.
At the university level, this role is to help the university develop a solid foundation that will support a strong safety culture. At this level, it can be a challenge to mobilize and sustain the necessary resources to effectively develop and communicate a clear, consistent message that is aligned with implicit and explicit reward structures
Disordered Bose Einstein Condensates with Interaction in One Dimension
We study the effects of random scatterers on the ground state of the
one-dimensional Lieb-Liniger model of interacting bosons on the unit interval
in the Gross-Pitaevskii regime. We prove that Bose Einstein condensation
survives even a strong random potential with a high density of scatterers. The
character of the wave function of the condensate, however, depends in an
essential way on the interplay between randomness and the strength of the
two-body interaction. For low density of scatterers or strong interactions the
wave function extends over the whole interval. High density of scatterers and
weak interaction, on the other hand, leads to localization of the wave function
in a fragmented subset of the interval
Exactness of the Bogoliubov approximation in random external potentials
We investigate the validity of the Bogoliubov c-number approximation in the
case of interacting Bose-gas in a \textit{homogeneous random} media. To take
into account the possible occurence of type III generalized Bose-Einstein
condensation (i.e. the occurrence of condensation in an infinitesimal band of
low kinetic energy modes without macroscopic occupation of any of them) we
generalize the c-number substitution procedure to this band of modes with low
momentum. We show that, as in the case of the one-mode condensation for
translation-invariant interacting systems, this procedure has no effect on the
exact value of the pressure in the thermodynamic limit, assuming that the
c-numbers are chosen according to a suitable variational principle. We then
discuss the relation between these c-numbers and the (total) density of the
condensate
Comparative measurements of total ozone amount and aerosol optical depth during a campaign at El Arenosillo, Huelva, Spain
A one week field campaign took place in September 2002 at El Arenosillo, Spain. The objective was to compare total ozone column (<I>TOC</I>) and aerosol optical depth (<I>AOD</I>) from near ultraviolet to near infrared, measured by several Spanish and French instruments. Three spectroradiometers, Brewer, SPUV02, and LICOR, and a CIMEL photometer, have been used simultaneously and the results are presented for four clear days. <I>TOC</I> values are given by the Brewer instrument, and by SPUV02, using two different methods. The ground instruments compare satisfactorily (within 5&nbsp;DU) and the values are consistent with TOMS data (within 10&nbsp;DU). <P style="line-height: 20px;"> <I>AOD</I> from the various instruments are compared at seven different wavelengths between 320 nm and 1020 nm: the agreement is very good at 350, 380, and 870 nm; at the four other wavelengths the difference is smaller than 0.03, which can be explained by a relative difference of 4% only between the calibrations of the various instruments. Larger <I>AOD</I> diurnal variations were observed at short wavelengths than in the visible and near infrared; this is most likely due to changes in aerosol size along the day, during the campaign
Social Science Considerations for Integrating Aviation Technology, Emergency Services, and Human Resilience
Unmanned aerial systems (UAS) have a range of innovative applications within the field of disaster management, underscoring the potential to enhance human security by integrating UAS across phases of disasters. This paper highlights important social science challenges that must be addressed to ensure the effective integration of UAS, the complex team of teams that respond to disasters, and the populations affected by disasters. Expanding upon points of intersection between UAS capabilities and disaster management identified in recent research, UAS uses in disaster management and corresponding psychosocial considerations are discussed. Broadly, these considerations focus on the training and development of the disaster management multiteam system (MTS) as well as the well-being of disaster responders and the populations they serve. Considerations for mitigation (resilient team infrastructure), preparation (education and training), response (an integrated MTS; responder health), and recovery (population resilience) phases of disaster management are discussed to pave the way for future research and application in this area
Measurements of UV aerosol optical depth in the French Southern Alps
Routine measurements of global and diffuse UV irradiances at Briançon station (1310 m a.s.l.) are used to retrieve the direct solar irradiance and the aerosol optical depth (AOD), for cloudless days. Data of three years (2003, 2004, 2005) are analyzed; the results confirm those of a preliminary analysis for 2001, 2002. <br><br> The atmosphere is very clear in winter, with AODs between 0.05 and 0.1. The turbidity increases slowly in spring, starting end of February, with AODs around 0.2–0.3 in mid summer, some values reaching 0.4. A similar behaviour is observed for all years, with somewhat higher values in late summer for the year 2003
Integrating Aviation Technology, Emergency Services, and Human Resilience: Considerations from Social Scientists
Unmanned aerial systems (UAS) have a range of applications within the field of disaster response. This presentation offers a novel framework of psychosocial considerations designed to advance UAS and disaster management integration. Social scientists highlight important challenges to the effective integration of three primary entities: UAS, the team of teams that responds to disasters, and populations affected by disasters.
The presentation adopts an emerging theoretical perspective on the intersection between UAS capabilities and disaster phases and extends it by bringing necessary attention to social science issues. Specifically, the framework outlines psychosocial considerations and areas of improvement for preparation (training), response (incident command), and recovery (occupational health; population resilience) phases of disaster management.
First, training curricula must involve the full disaster response multiteam system (MTS; i.e., team of teams) in cross-training that builds a shared identity by operationalizing UAS as a component team. Second, disaster response MTSs must establish incident command structures that incorporate UAS into team communication and coordination networks. Third, the implications of stressors unique to UAS operation need to be better understood in the context of existing cyclical effects of work stress on disaster responder performance and well-being. Finally, as crisis communication affects disaster-impacted communities, populations must be able to leverage UAS as a mechanism for, and not a barrier against, recovery from disaster.
Across the globe, disasters threaten human security. This presentation provides a necessary interdisciplinary perspective on implementing UAS in disaster management to help the world better prepare for, respond to, recover from, and mitigate disasters
Physical Behavior in Older Persons during Daily Life: Insights from Instrumented Shoes.
Activity level and gait parameters during daily life are important indicators for clinicians because they can provide critical insights into modifications of mobility and function over time. Wearable activity monitoring has been gaining momentum in daily life health assessment. Consequently, this study seeks to validate an algorithm for the classification of daily life activities and to provide a detailed gait analysis in older adults. A system consisting of an inertial sensor combined with a pressure sensing insole has been developed. Using an algorithm that we previously validated during a semi structured protocol, activities in 10 healthy elderly participants were recorded and compared to a wearable reference system over a 4 h recording period at home. Detailed gait parameters were calculated from inertial sensors. Dynamics of physical behavior were characterized using barcodes that express the measure of behavioral complexity. Activity classification based on the algorithm led to a 93% accuracy in classifying basic activities of daily life, i.e., sitting, standing, and walking. Gait analysis emphasizes the importance of metrics such as foot clearance in daily life assessment. Results also underline that measures of physical behavior and gait performance are complementary, especially since gait parameters were not correlated to complexity. Participants gave positive feedback regarding the use of the instrumented shoes. These results extend previous observations in showing the concurrent validity of the instrumented shoes compared to a body-worn reference system for daily-life physical behavior monitoring in older adults
- …