666 research outputs found
Modelling mineral dust using stereophotogrammetry
Real, three-dimensional shape of a dust particle is derived from a pair of scanning-electron microscope images by means of stereophotogrammetry. The resulting shape is discretized, and preliminary discrete-dipole-approximation computations for the single dust particle reveal that scattering by such an irregular shape differs notably from scattering by a sphere or a Gaussian random sphere which both are frequently used shape models for dust particles
Single scattering by realistic, inhomogeneous mineral dust particles with stereogrammetric shapes
Light scattering by single, inhomogeneous mineral dust particles was
simulated based on shapes and compositions derived directly from measurements
of real dust particles instead of using a mathematical shape model. We
demonstrate the use of the stereogrammetric shape retrieval method in the context
of single-scattering modelling of mineral dust for four different dust types
â all of them inhomogeneous â ranging from compact, equidimensional shapes
to very elongated and aggregate shapes. The three-dimensional particle shapes
were derived from stereo pairs of scanning-electron microscope images, and
inhomogeneous composition was determined by mineralogical interpretation of
localized elemental information based on energy-dispersive spectroscopy.
Scattering computations were performed for particles of equal-volume
diameters, from 0.08 ÎŒm up to 2.8 ÎŒm at 550 nm wavelength, using the
discrete-dipole approximation. Particle-to-particle variation in scattering
by mineral dust was found to be quite considerable and was not well
reproduced by simplified shapes of homogeneous spheres, spheroids, or
Gaussian random spheres. Effective-medium approximation results revealed that
particle inhomogeneity should be accounted for even for small amounts of
absorbing media (here up to 2% of the volume), especially when considering
scattering by inhomogeneous particles at size parameters 3<<i>x</i><8. When
integrated over a log-normal size distribution, the linear depolarization
ratio and single-scattering albedo were also found to be sensitive to
inhomogeneity. The methodology applied is work-intensive and the
light-scattering method used quite limited in terms of size parameter
coverage. It would therefore be desirable to find a sufficiently accurate but
simpler approach with fewer limitations for single-scattering modelling of
dust. For validation of such a method, the approach presented here could be
used for producing reference data when applied to a suitable set of target
particles
Dialogue based interfaces for universal access.
Conversation provides an excellent means of communication for almost all people. Consequently, a conversational interface is an excellent mechanism for allowing people to interact with systems. Conversational systems are an active research area, but a wide range of systems can be developed with current technology. More sophisticated interfaces can take considerable effort, but simple interfaces can be developed quite rapidly. This paper gives an introduction to the current state of the art of conversational systems and interfaces. It describes a methodology for developing conversational interfaces and gives an example of an interface for a state benefits web site. The paper discusses how this interface could improve access for a wide range of people, and how further development of this interface would allow a larger range of people to use the system and give them more functionality
Forward-Looking Sustainability Agency for Developing Future Cruise Ships
The study addressed sharing of futures insights as a component of
sustainability agency for long-term company enhancement in an
interorganizational shipbuildersâ network. The purpose was to analyze
social structures under âagencyâ terminology. This joint sustainability
project involved a partnership of firms, academia, and nongovernmental
organization (NGO) actors in collaborative cruise ship building. The
study adapted a mixed method approach where social network analysis
(SNA) was enriched with other contextual data to make network data more
applicable and accessible. The results revealed a loose and thin network
structure, with relatively high trust among network actors. The
networkâs social structure was found to facilitate insight sharing. Lead
firm actors clearly played a central role in enhancing sustainability,
and the researchers, as well as industrial association actors, made a
significant contribution to insight sharing and transmission. The
findings suggest that the case network would benefit from an open and
balanced social structure that incorporates a number of insight brokers
to enhance forward-looking sustainability agency (F-L SA). Futures
insight sharing enhances agency in the context of joint sustainability
actions and improves capacity to respond to systemic challenges.
Understanding how proactive agency can be promoted in network settings
strengthens strategic aspects of managerial practice and contributes to
discourse around sustainability agency</p
Morphine-3-glucuronide causes antinociceptive cross-tolerance to morphine and increases spinal substance P expression
Morphine-3-glucuronide (M3G), the main metabolite of morphine, has been implicated in the development of tolerance and of opioid-induced hyperalgesia, both limiting the analgesic use of morphine. We evaluated the acute and chronic effects of M3G and morphine as well as development of antinociceptive cross-tolerance between morphine and M3G after intrathecal administration and assessed the expression of pain-associated neurotransmitter substance P in the spinal cord. Sprague-Dawley rats received intrathecal M3G or morphine twice daily for 6 days. Nociception and tactile allodynia were measured with von Frey filaments after acute and chronic treatments. Substance P levels in the dorsal horn of the spinal cord were determined by immunohistochemistry after 4-day treatments. Acute morphine caused antinociception as expected, whereas acute M3G caused tactile allodynia, as did both chronic M3G and morphine. Chronic M3G also induced antinociceptive cross-tolerance to morphine. M3G and morphine increased substance P levels similarly in the nociceptive laminae of the spinal cord. This study shows that chronic intrathecal M3G sensitises animals to mechanical stimulation and elevates substance P levels in the nociceptive laminae of the spinal cord. Chronic M3G also induces antinociceptive cross-tolerance to morphine. Thus, chronic M3G exposure might contribute to morphine-induced tolerance and opioid-induced hyperalgesia.Peer reviewe
Geographic origin as a determinant of left ventricular mass and diastolic function - the Cardiovascular Risk in Young Finns Study
Aims: Eastern Finns have higher risk of coronary heart disease (CHD) and carotid intima-media thickness than western Finns although current differences in CHD risk factors are minimal. Left ventricular (LV) mass and diastolic function predict future cardiovascular events but their east-west differences are unknown. We examined the association of eastern/western baseline origin with LV mass and diastolic function. Methods : The study population included 2045 subjects of the Cardiovascular Risk in Young Finns Study with data from the baseline survey (1980) and the latest follow-up (2011) when echocardiography was performed at the age of 34-49 years. Results: Subjects with eastern baseline origin had in 2011 higher LV mass (139 +/- 1.0 vs. 135 +/- 1.0 g, p=0.006) and E/e-ratio indicating weaker LV diastolic function (4.86 +/- 0.03 vs. 4.74 +/- 0.03, p=0.02) than western subjects. Results were independent of age, sex, area of examination and CHD risk factors such as blood pressure and BMI (LV mass indexed with height: pPeer reviewe
Proton dripline studies at ISOLDE: Ar and C
In this contribution examples of the application of new technologies to disentangle the mechanism of -delayed multiparticle emission are given. In particular the mechanism of 2p-emission from Ar has been resolved and proved to be sequential, a preview of C-decay data is discussed
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