762 research outputs found
Is Community Informatics Good for Communities? Questions Confronting an Emerging Field
This paper addresses a number of questions confronting the emerging field of community informatics. First, is it a field of study or a field of practice? Second, is the focus of community informatics on communities, information, or technology? Third, does community informatics serve elites, academics, community workers, or community workers? The paper moves from these questions to develop an empowerment model for community informations, emphasizing a community development approach combined with an information focus and a participatory process. It concludes with the question of whether community informatics should strive to be a supporting field rather than develop as an independent arena of study or practice
The thermodynamics for a hadronic gas of fireballs with internal color structures and chiral fields
The thermodynamical partition function for a gas of color-singlet bags
consisting of fundamental and adjoint particles in both and
group representations is reviewed in detail. The constituent particle species
are assumed to satisfy various thermodynamical statistics. The gas of bags is
probed to study the phase transition for a nuclear matter in the extreme
conditions. These bags are interpreted as the Hagedorn states and they are the
highly excited hadronic states which are produced below the phase transition
point to the quark-gluon plasma. The hadronic density of states has the
Gross-Witten critical point and exhibits a third order phase transition from a
hadronic phase dominated by the discrete low-lying hadronic mass spectrum
particles to another hadronic phase dominated by the continuous Hagedorn
states. The Hagedorn threshold production is found just above the highest known
experimental discrete low-lying hadronic mass spectrum. The subsequent Hagedorn
phase undergoes a first order deconfinement phase transition to an explosive
quark-gluon plasma. The role of the chiral phase transition in the phases of
the discrete low-lying mass spectrum and the continuous Hagedorn mass spectrum
is also considered. It is found crucial in the phase transition diagram.
Alternate scenarios are briefly discussed for the Hagedorn gas undergoes a
higher order phase transition through multi-processes of internal color-flavor
structure modification.Comment: 110 pages and 13 figures. Added references to the introductio
Changes in the Sea-Ice Brine Community During the Spring-Summer Transition, McMurdo Sound, Antarctica .2. Phagotrophic Protists
The land-fast sea-ice brine contains a diverse phagotrophic protist assemblage consisting of \u3c 5 mum heterotrophic flagellates, Cryothecomonas spp., heterotrophic dinoflagellates, and heterotrophic and mixotrophic ciliates. Fine-scale horizontal spatial variability is a feature of this assemblage; samples taken within 1 m of each other can be dominated by different heterotrophic protists. Many of the larger heterotrophic protists found in the brine are also found in the water column. The photosynthetic ciliate Mesodinium rubrum is also common. In mid to late austral spring, the heterotrophic assemblage accounts for ca 10% of the total protist biomass in the brine and is dominated by Cryothecomonas spp. This flagellate can reach densities of over 106 cells l-1 of brine. In the early austral summer, ciliates (primarily Strombidium spp., Mesodinium rubrum and Didinium spp.) and heterotrophic dinoflagellates (primarily a small Gymnodinium sp. and Polykrikos sp.) increase in abundance in the brine. Ciliate densities of ≥ 3 x 103 l-1 and heterotrophic dinoflagellate densities of 104 cells l-1 are common in the brine during early summer. By the end of January (just prior to ice decay and break-out), heterotrophic flagellates and ciliates can account for 50 % of the protist biomass
Neutron-Star-Merger Equation of State
In this work, we discuss the dense matter equation of state (EOS) for the
extreme range of conditions encountered in neutron stars and their mergers. The
calculation of the properties of such an EOS involves modeling different
degrees of freedom (such as nuclei, nucleons, hyperons, and quarks), taking
into account different symmetries, and including finite density and temperature
effects in a thermodynamically consistent manner. We begin by addressing
subnuclear matter consisting of nucleons and a small admixture of light nuclei
in the context of the excluded volume approach. We then turn our attention to
supranuclear homogeneous matter as described by the Chiral Mean Field (CMF)
formalism. Finally, we present results from realistic neutron-star-merger
simulations performed using the CMF model that predict signatures for
deconfinement to quark matter in gravitational wave signals.Comment: Contribution to the Special Issue "Compact Stars in the QCD Phase
Diagram and in the Multi-Messenger Era of Astronomy" dedicated to the
conference: Compact Stars in the QCD Phase Diagram VI
Micro-canonical pentaquark production in \ee annihilations
The existence of pentaquarks, namely baryonic states made up of four quarks
and one antiquark, became questionable, because the candidates, i.e. the
peak, are seen in certain reactions, i.e. p+p collisions, but not in
others, i.e. \ee annihilations. In this paper, we estimate the production of
and in \ee annihilations at different
energies using Fermi statistical model as originally proposed in its
microcanonical form. The results is compared with that from pp collisions at
SPS and RHIC energies. We find that, if pentaquark states exist, the production
is highly possible in \ee annihilations. For example, at LEP energy
=91.2 GeV, both and yield more
than in pp collisions at SPS and RHIC energy.Comment: 7 pages 2 figure
Microwave Reflectometry as a Novel Diagnostic Method for Detection of Skin Cancers
More than one million people are diagnosed with skin cancer each year in the United States and more than ten thousand people die from the disease. Currently, there are some methods for early detection of skin cancers, like visual inspection, but improvements are needed. This paper presents a method involving microwave reflectometry as a diagnostic tool for detection of skin cancers. The results of measurements and simulations for normal and wet skin have been shown to distinguish among skin samples with different properties. Microwave measurements from lesions have also been presented which are used to distinguish between cancerous and benign lesions
Fuzzy Color Clustering for Melanoma Diagnosis in Dermoscopy Images
A fuzzy logic-based color histogram analysis technique is presented for discriminating benign skin lesions from malignant melanomas in dermoscopy images. The approach extends previous research for utilizing a fuzzy set for skin lesion color for a specified class of skin lesions, using alpha-cut and support set cardinality for quantifying a fuzzy ratio skin lesion color feature. Skin lesion discrimination results are reported for the fuzzy clustering ratio over different regions of the lesion over a data set of 517 dermoscopy images consisting of 175 invasive melanomas and 342 benign lesions. Experimental results show that the fuzzy clustering ratio applied over an eight-connected neighborhood on the outer 25% of the skin lesion with an alpha-cut of 0.08 can recognize 92.6% of melanomas with approximately 13.5% false positive lesions. These results show the critical importance of colors in the lesion periphery. Our fuzzy logic-based description of lesion colors offers relevance to clinical descriptions of malignant melanoma
Microwave Reflectometry As a Novel Diagnostic Tool for Detection of Skin Cancers
More than 1 000 000 people are diagnosed with skin cancer each year in the United States, and more than 10 000 people die from the disease. Methods such as visual inspection and dermoscopy are available for early detection of skin cancers, but improvement in accuracy is needed. This paper investigates the use of microwave reflectometry as a potential diagnostic tool for detection of skin cancers. Open-ended coaxial probes were used to measure microwave properties of skin. The influences of measurement parameters such as probe application pressure, power level, and variation in reflection properties of skin with location and hydration were investigated. Using an available electromagnetic formulation, providing for the reflection properties of a layered dielectric structure irradiated by a coaxial probe, measurement and simulation results were compared. The results of the measurements and simulations for normal and moistened skin show that the water content of normal skin and benign and malignant lesions may cause significant differences among their reflection properties and subsequently render a malignant lesion detectable. The results of microwave measurements performed on human subjects are also presented, which show the potential of this technique to distinguish between cancerous and benign lesions
Skin Scan Digital Dermoscopy Skin Cancer Training Software
Computational Infrastructure and Informatics Poster SessionSkin Scan digital dermoscopy skin cancer detection software, developed by Rolla's S&A in collaboration with Missouri S&T, can now detect critical features of early melanoma. There is also a need for diagnostic help for the other 95+% of skin cancers. The need for diagnostic improvement in screening for skin cancers may be greatest for those nurse practitioners who now see the majority of elderly patients in some underserved areas. Underserved clinical arenas with a greater than average incidence of skin cancer and a significant number of nurse practitioners include both civilian and military clinics in the rural Midwest, where S&A is located. This innovative software is a timely development designed to solve problems every healthcare consumer has encountered: too long a wait to get specialty care, uncertainty about the diagnosis when one does get the care, and too much overall expenditure in providing the care. Our ongoing research includes a completed Phase II project in melanoma detection and a Phase I study for basal cell carcinoma, submitted December, 2009. The BASAL features for basal cell carcinoma (Blue-gray ovoids, Arborizing telangiectasia, Semitranslucency, Atraumatic ulceration, and Leaf-like structures/dirt trails), described by Stoecker and Stolz, Archives Dermatology 2008, will be programmed during Phase I of the new proposal and incorporated in our early detection system. Additional work during Phase I will allow acquisition of more clinical and dermoscopy images, will allow training of the first nurse practitioner, and will allow development of a hierarchical neural network for diagnosis of basal cell carcinoma
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