1,611 research outputs found
Erfahrungswissenschaft und Expertenblick -Eine Forschungsmethode inspiriert von der biologisch-dynamischen Landwirtschaft
Experiential science is based on the unique knowledge gathered by experienced practitioners. Both the reflective evaluation of case studies and expert judgement processes and the use of pattern recognition are core elements of experiential scien-tific methodology. Development of experiential knowledge and insights are thus pri-marily based on expertsâ actions and the reflections on those actions. The methodol-ogy has been created based on intensive cooperation between single farmers or farmer groups and scientists/advisors. Experiential knowledge is not only holistic, but also adequate. As in formal science, experienced practitioners develop valid knowl-edge and in new, unknown situations they have a capability to integrate their diagno-sis (âknowing whatâ) and suitable actions, necessary at a specific time (âknowing thatâ)
The South African township funeral : a 'site of resistance' of HIV and AIDS that promotes leading causes of life
Includes bibliographical references (p. 86-90).Is a South African township funeral a 'site of resistance' to HIV which provides communities with a means for achieving a telos of health? Could the funeral embody the leading causes of life (a theory used to develop the analysis) needed to create and sustain life in the midst of illness and death? This study will seek to answer these questions through a close look at the J L Zwane Church and Community Centre, a faith based community in Gugulethu, South Africa. By exploring township funerals of the apartheid past in relation to funerals resulting from the AIDS epidemic, despite what many construe as decay and death, ample evidence of resiliency and life will be demonstrated
Detection of Optical Synchrotron Emission from the Radio Jet of 3C279
We report the detection of optical and ultraviolet emission from the
kiloparsec scale jet of the well-known quasar 3C~279. A bright knot, discovered
in archival V and U band {\it Hubble Space Telescope} Faint Object Camera
images, is coincident with a peak in the radio jet \sim0.6\arcsec from the
nucleus. The detection was also confirmed in Wide Field Planetary Camera-2
images. Archival Very Large Array and MERLIN radio data are also analyzed which
help to show that the high-energy optical/UV continuum, and spectrum, are
consistent with a synchrotron origin from the same population of relativistic
electrons responsible for the radio emission.Comment: 6 pages, 3 figs. accepted for publication in ApJL with minor
revision
The Evolution of Cas A at Low Radio Frequencies
We have used archival 74 MHz VLA data spanning the last 15 years in
combination with new data from the Long Wavelength Demonstrator Array (LWDA)
and data from the literature covering the last 50 years to explore the
evolution of Cas A at low radio frequencies. We find that the secular decrease
of the flux density of Cas A at ~80 MHz is rather stable over five decades of
time, decreasing at a rate of 0.7-0.8% yr^-1. This is entirely consistent with
previous estimates at frequencies as low as 38 MHz, indicating that the secular
decrease is roughly the same at low frequencies, at least between 38 and 80
MHz. We also find strong evidence for as many as four modes of flux density
oscillation about the slower secular decrease with periods of 3.10+/-0.02$ yr,
5.1+/-0.3 yr, 9.0+/-0.2 yr, and 24+/-2 yr. These are also consistent with
fluctuations seen previously to occur on scales of a few years. These results
provide compelling motivation for a thorough low frequency monitoring campaign
of Cas A to constrain the nature and physical origins of these fluctuations,
and to be able to better predict the flux density of Cas A at any given epoch
so that it may be used as a reliable low frequency calibrator.Comment: accepted for publication in A
Thermal design issues and performance of microcalorimeter arrays at sub-Kelvin temperatures
We have produced 5/spl times/5 pixel arrays of microcalorimeters using bulk micromachining. Analysis of our data provides the thermal conductivity parameters of Si/sub x/N/sub y/ 1 /spl mu/m thick membranes at 100 mK. Moreover we find that the thermal transport at 100 mK in Si beams, with dimensions 1.25 mm /spl times/ 0.35mm /spl times/ 35/spl mu/m (length /spl times/ height /spl times/ width) is dominated by ballistic phonons with a mean free path of 110 /spl mu/m. These thermal parameters can be used for modelling future 32 /spl times/ 32 pixel arrays. In addition we operated three pixels in a 5 /spl times/ 5 array of microcalorimeters and find that the pixel to pixel reproducibility is very good. When used as an X-ray microcalorimeter individual pixels have a thermal decay time of 200 /spl mu/s is and their energy resolution is between 6 and 7 eV for 5.89 keV X-ray photons
L1CAM binds ErbB receptors through Ig-like domains coupling cell adhesion and neuregulin signalling.
During nervous system development different cell-to-cell communication mechanisms operate in parallel guiding migrating neurons and growing axons to generate complex arrays of neural circuits. How such a system works in coordination is not well understood. Cross-regulatory interactions between different signalling pathways and redundancy between them can increase precision and fidelity of guidance systems. Immunoglobulin superfamily proteins of the NCAM and L1 families couple specific substrate recognition and cell adhesion with the activation of receptor tyrosine kinases. Thus it has been shown that L1CAM-mediated cell adhesion promotes the activation of the EGFR (erbB1) from Drosophila to humans. Here we explore the specificity of the molecular interaction between L1CAM and the erbB receptor family. We show that L1CAM binds physically erbB receptors in both heterologous systems and the mammalian developing brain. Different Ig-like domains located in the extracellular part of L1CAM can support this interaction. Interestingly, binding of L1CAM to erbB enhances its response to neuregulins. During development this may synergize with the activation of erbB receptors through L1CAM homophilic interactions, conferring diffusible neuregulins specificity for cells or axons that interact with the substrate through L1CAM
De Hoge Born verbindt: kwaliteiten en effecten van zorgboerderij De Hoge Born
De Hoge Born blijkt voor zorgvragers een plek te zijn 'waar je mag zijn wie je bent', waar 'je jezelf met je problemen leert accepteren' en 'zelfvertrouwen en eigenwaarde ontwikkelt'. Dit legt een basis voor hun verdere ontwikkeling. Bij de meeste zorgvragers die langere tijd zijn gevolgd met het monitoringsinstrument werden betrouwbare positieve veranderingen vastgestel
Citrus/Cydonia Comp. Can Restore the Immunological Balance in Seasonal Allergic Rhinitis-Related Immunological Parameters In Vitro
In two in vitro studies, we examined the immunological (pathways of the) effects of Citrus/Cydonia comp. from, respectively, a healthy and an allergic donor; peripheral blood mononuclear cells (PBMCs) were isolated out of peripheral blood and analyzed in vitro after polyclonal stimulation of T-cells. The differentiation capacity and the influence with regard to Th1 (IFN-Îł) and Th2 (IL-5) cells were examined. Citrus/Cydonia comp. has a selective effect on the differentiation of T-cells by producing relatively more IL-10 than IL-12. By that, it also seems to have an effect on the induction of regulatory (IL-10 producing) T-cell subsets. It is in vitro capable of neutralizing (to some extent) the changes, characteristic to allergic rhinitis, with regard to the maturation, differentiation, and activity of the immune system. Thus, Citrus/Cydonia comp. can potentially restore the disturbed immune state of rhinitis patients, which essentially could be sufficient to make allergic symptoms disappear permanently
Radio Emission from the Intermediate-mass Black Hole in the Globular Cluster G1
We have used the Very Large Array (VLA) to search for radio emission from the
globular cluster G1 (Mayall-II) in M31. G1 has been reported by Gebhardt et al.
to contain an intermediate-mass black hole (IMBH) with a mass of ~2 x 10^4
solar masses. Radio emission was detected within an arcsecond of the cluster
center with an 8.4 GHz power of 2 x 10^{15} W/Hz. The radio/X-ray ratio of G1
is a few hundred times higher than that expected for a high-mass X-ray binary
in the cluster center, but is consistent with the expected value for accretion
onto an IMBH with the reported mass. A pulsar wind nebula is also a possible
candidate for the radio and X-ray emission from G1; future high-sensitivity
VLBI observations might distinguish between this possibility and an IMBH. If
the radio source is an IMBH, and similar accretion and outflow processes occur
for hypothesized ~ 1000-solar-mass black holes in Milky Way globular clusters,
they are within reach of the current VLA and should be detectable easily by the
Expanded VLA when it comes on line in 2010.Comment: ApJ Letters, accepted, 11 pages, 1 figur
Cicrumnuclear Supernova Remnants and HII Regions in NGC 253
Archival VLA data has been used to produce arcsecond-resolution 6- and 20-cm
images of the region surrounding the nuclear 200-pc (~15") starburst in NGC
253. Twenty-two discrete sources stronger than 0.4 mJy have been detected
within ~2 kpc (~3') of the galaxy nucleus; almost all these sources must be
associated with the galaxy. None of the radio sources coincides with a detected
X-ray binary, so they appear to be due to supernova remnants and H II regions.
The region outside the central starburst has a derived radio supernova rate of
<~0.1/yr, and may account for at least 20% of the recent star formation in NGC
253. Most of the newly identified sources have steep, nonthermal radio spectra,
but several relatively strong thermal sources also exist, containing the
equivalent of tens of O5 stars. These stars are spread over tens of parsecs,
and are embedded in regions having average ionized gas densities of
20-200/cm^3, much lower than in the most active nuclear star-forming regions in
NGC 253 or in the super star clusters seen in other galaxies. The strongest
region of thermal emission coincides with a highly reddened area seen at
near-infrared wavelengths, possibly containing optically obscured H II regions.Comment: 17 pages, 3 postscript figures, AASTeX format, in press for
Astronomical Journal, July 200
- âŠ