7,660 research outputs found
Report of the Subgroup on Alternative Models and New Ideas
We summarize some of the work done by the P3 subgroup on Alternative Models
and New Ideas. The working group covered a broad range of topics including a
constrained Standard Model from an extra dimension, a discussion of recent
ideas addressing the strong CP problem, searches for doubly charged higgs
bosons in e gamma collisions, and an update on discovery limits for extra
neutral gauge bosons at hadron colliders. The breadth of topics reflects the
many ideas and approaches to physics beyond the Standard Model.Comment: 10 pages, 5 figures. Contributed to the APS/DPF/DPB Summer Study on
the Future of Particle Physics (Snowmass 2001), Snowmass, Colorado, 30 Jun -
21 Jul 200
Interactions of Heavy Hadrons using Regge Phenomenology and the Quark Gluon String Model
The search for stable heavy exotic hadrons is a promising way to observe new
physics processes at collider experiments. The discovery potential for such
particles can be enhanced or suppressed by their interactions with detector
material. This paper describes a model for the interactions in matter of stable
hadrons containing an exotic quark of charges or
using Regge phenomenology and the Quark Gluon String Model. The influence of
such interactions on searches at the LHC is also discussed
Indirect Low-Intensity Ultrasonic Stimulation for Tissue Engineering
Low-intensity ultrasound (LIUS) treatment has been shown to increase mass transport, which could benefit tissue grafts during the immediate postimplant period, when blood supply to the implanted tissue is suboptimal. In this in vitro study, we investigated effects of LIUS stimulation on dye diffusion, proliferation, metabolism, and tropomyosin expression of muscle cells (C2C12) and on tissue viability and gene expression of human adipose tissue organoids.
We found that LIUS increased dye diffusion within adjacent tissue culture wells and caused anisotropic diffusion patterns. This effect was confirmed by a hydrophone measurement resulting in acoustic pressure 150–341 Pa in wells. Cellular studies showed that LIUS significantly increased proliferation, metabolic activity, and expression of tropomyosin. Adipose tissue treated with LIUS showed significantly increased metabolic activity and the cells had similar morphology to normal unilocular adipocytes. Gene analysis showed that tumor necrosis factor-alpha expression (a marker for tissue damage) was significantly lower for stimulated organoids than for control groups. Our data suggests that LIUS could be a useful modality for improving graft survival in vivo
Magnetic Flux of EUV Arcade and Dimming Regions as a Relevant Parameter for Early Diagnostics of Solar Eruptions - Sources of Non-Recurrent Geomagnetic Storms and Forbush Decreases
This study aims at the early diagnostics of geoeffectiveness of coronal mass
ejections (CMEs) from quantitative parameters of the accompanying EUV dimming
and arcade events. We study events of the 23th solar cycle, in which major
non-recurrent geomagnetic storms (GMS) with Dst <-100 nT are sufficiently
reliably identified with their solar sources in the central part of the disk.
Using the SOHO/EIT 195 A images and MDI magnetograms, we select significant
dimming and arcade areas and calculate summarized unsigned magnetic fluxes in
these regions at the photospheric level. The high relevance of this eruption
parameter is displayed by its pronounced correlation with the Forbush decrease
(FD) magnitude, which, unlike GMSs, does not depend on the sign of the Bz
component but is determined by global characteristics of ICMEs. Correlations
with the same magnetic flux in the solar source region are found for the GMS
intensity (at the first step, without taking into account factors determining
the Bz component near the Earth), as well as for the temporal intervals between
the solar eruptions and the GMS onset and peak times. The larger the magnetic
flux, the stronger the FD and GMS intensities are and the shorter the ICME
transit time is. The revealed correlations indicate that the main quantitative
characteristics of major non-recurrent space weather disturbances are largely
determined by measurable parameters of solar eruptions, in particular, by the
magnetic flux in dimming areas and arcades, and can be tentatively estimated in
advance with a lead time from 1 to 4 days. For GMS intensity, the revealed
dependencies allow one to estimate a possible value, which can be expected if
the Bz component is negative.Comment: 27 pages, 5 figures. Accepted for publication in Solar Physic
Solar flare-related eruptions followed by long-lasting occultation of the emission in the He II 304 A line and in microwaves
Plasma with a temperature close to the chromospheric one is ejected in solar
eruptions. Such plasma can occult some part of emission of compact sources in
active regions as well as quiet solar areas. Absorption phenomena can be
observed in the microwave range as the so-called 'negative bursts' and also in
the He II 304 A line. The paper considers three eruptive events associated with
rather powerful flares. Parameters of absorbing material of an eruption are
estimated from multi-frequency records of a 'negative burst' in one event.
'Destruction' of an eruptive filament and its dispersion like a cloud over a
huge area observed as a giant depression of the 304 A line emission has been
revealed in a few events. One such event out of three ones known to us is
considered in this paper. Another event is a possibility.Comment: 23 pages, 8 figures, submitted for publication in Astronomy Report
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