8,856 research outputs found
On the probability distribution function of small scale interplanetary magnetic field fluctuations
In spite of a large number of papers dedicated to study MHD turbulence in the
solar wind there are still some simple questions which have never been
sufficiently addressed like: a)do we really know how the magnetic field vector
orientation fluctuates in space? b) what is the statistics followed by the
orientation of the vector itself? c) does the statistics change as the wind
expands into the interplanetary space? A better understanding of these points
can help us to better characterize the nature of interplanetary fluctuations
and can provide useful hints to investigators who try to numerically simulate
MHD turbulence. This work follows a recent paper presented by the same authors.
This work follows a recent paper presented by some of the authors which shows
that these fluctuations might resemble a sort of random walk governed by a
Truncated Leevy Flight statistics. However, the limited statistics used in that
paper did not allow final conclusions but only speculative hypotheses. In this
work we aim to address the same problem using a more robust statistics which on
one hand forces us not to consider velocity fluctuations but, on the other hand
allows us to establish the nature of the governing statistics of magnetic
fluctuations with more confidence. In addition, we show how features similar to
those found in the present statistical analysis for the fast speed streams of
solar wind, are qualitatively recovered in numerical simulations of the
parametric instability. This might offer an alternative viewpoint for
interpreting the questions raised above.Comment: 25pag, 20 jpg small size figures. In press on "ANnales Geophysicae"
(September 2004
ATLAS RPC Quality Assurance results at INFN Lecce
The main results of the quality assurance tests performed on the Resistive
Plate Chamber used by the ATLAS experiment at LHC as muon trigger chambers are
reported and discussed.
Since July 2004, about 270 RPC units has been certified at INFN Lecce site
and delivered to CERN, for being integrated in the final muon station of the
ATLAS barrel region.
We show the key RPC characteristics which qualify the performance of this
detector technology as muon trigger chamber in the harsh LHC enviroments.
These are dark current, chamber efficiency, noise rate, gas volume
tomography, and gas leakage.Comment: Comments: 6 pages, 1 table, 9 figures Proceedings of XXV Physics in
Collision-Prague, Czech Republic, 6-9 July 200
ATLAS RPC Cosmic Ray Teststand at INFN Lecce
We describe the design and functionality of the cosmic ray teststand built at
INFN Lecce for ATLAS RPC quality control assurance.Comment: XXIV Physics in Collisions Conference (PIC04), Boston, USA, June
2004, 3 pages, LaTex, 2 eps figures. MONP0
Promoting Family Literacy: An Opportunity for Suburban University-Inner City Agency Resource Exchange
The Family Literacy Project is a preventive program designed to increase lower income children\u27s language readiness for school. The project\u27s approach to literacy enhancement involves both tutoring the children and training the parents to be more effective first teachers of the types of emergent reading skills that are prerequisites to formal elementary school reading instruction. Forty-five undergraduates were trained as literacy facilitators and met on a weekly basis with ninety preschoolers enrolled in Head start or with participating parents (N=20) . The specific tutoring of the children varied according to the child\u27s specific areas of language strengths and weaknesses. The parent training utilized the Parents as Partners in Reading literacy curriculum (Edwards, 1990)
Growth characteristics of American Ginseng (Panax quinquefolius L.) woods and field - cultivated at Northern Europe
Received: February 19th, 2022 ; Accepted: May 15th, 2022 ; Published: May 16th, 2022 ; Correspondence: [email protected] Latvia, Northern Europe, American ginseng was grown in three forest types with
different dominant species, as well as in agricultural field conditions - cultivated under artificial
shade with three different types of mulches. Field cultivation yielded higher yields, root length,
and root weight than wood cultivation under dominant species Corylus avellana, Betula pendula,
and Picea abies. Mulching had a positive impact on ginseng growth in the field. Mulching with
straw and buckwheat hulls resulted in longer and heavier roots.
In American ginseng roots, the contents of six ginsenosides were determined: Rg1, Re, Rb1, Rc,
Rb2, and Rd. Re was the most abundant ginsenoside, followed by Rb1 > Rd > Rg1 = Rb2 > Rd.
The total content of ginsenosides in our study did not reach the 4 percent threshold set by US
Pharmacopeia.
These findings show that Panax quinquefolium can be grown in Northern Europe at 57°N, but it
takes more than four years to achieve adequate yields and ginsenoside content
Proper orthogonal decomposition of solar photospheric motions
The spatio-temporal dynamics of the solar photosphere is studied by
performing a Proper Orthogonal Decomposition (POD) of line of sight velocity
fields computed from high resolution data coming from the MDI/SOHO instrument.
Using this technique, we are able to identify and characterize the different
dynamical regimes acting in the system. Low frequency oscillations, with
frequencies in the range 20-130 microHz, dominate the most energetic POD modes
(excluding solar rotation), and are characterized by spatial patterns with
typical scales of about 3 Mm. Patterns with larger typical scales of 10 Mm, are
associated to p-modes oscillations at frequencies of about 3000 microHz.Comment: 8 figures in jpg in press on PR
Ageing test of the ATLAS RPCs at X5-GIF
An ageing test of three ATLAS production RPC stations is in course at X5-GIF,
the CERN irradiation facility. The chamber efficiencies are monitored using
cosmic rays triggered by a scintillator hodoscope. Higher statistics
measurements are made when the X5 muon beam is available. We report here the
measurements of the efficiency versus operating voltage at different source
intensities, up to a maximum counting rate of about 700Hz/cm^2. We describe the
performance of the chambers during the test up to an overall ageing of 4 ATLAS
equivalent years corresponding to an integrated charge of 0.12C/cm^2, including
a safety factor of 5.Comment: 4 pages. Presented at the VII Workshop on Resistive Plate Chambers
and Related Detectors; Clermont-Ferrand October 20th-22nd, 200
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