7,722 research outputs found
Why frequencies are natural
Research in mathematical cognition has shown that rates, and other interpretations of x/y, are hard to learn and understand. On the other hand, there is extensive evidence that the brain is endowed with a specialized mechanism for representing and manipulating the numerosities of sets – that is, frequencies. Hence, base-rates are neglected precisely because they are rates, whereas frequencies are indeed natural
State-of-Science review: learning difficulties: SR-D4: Dyscalculia
Low numeracy skills in general and developmental dyscalculia (DD) in particular constitute
a severe handicap. This review examines the causes and behavioural manifestations of
numeracy deficits, their neuropsychological correlates and the limits to our understanding of
these conditions. It then goes on to describe a validated test for diagnosing DD – a specific
impairment in the capacity to learn arithmetic. The challenges in educating DD children and
analysing their particular intervention needs are described. Reference is also made to the
impact of dyscalculia on mental health (and ill-health) and individual wellbeing
The CEDAR Project
We describe the plans and objectives of the CEDAR project (Combined e-Science
Data Analysis Resource for High Energy Physics) newly funded by the PPARC
e-Science programme in the UK. CEDAR will combine the strengths of the well
established and widely used HEPDATA database of HEP data and the innovative
JetWeb data/Monte Carlo comparison facility, built on the HZTOOL package, and
will exploit developing grid technology. The current status and future plans of
both of these individual sub-projects within the CEDAR framework are described,
showing how they will cohesively provide (a) an extensive archive of Reaction
Data, (b) validation and tuning of Monte Carlo programs against these reaction
data sets, and (c) a validated code repository for a wide range of HEP code
such as parton distribution functions and other calculation codes used by
particle physicists. Once established it is envisaged CEDAR will become an
important Grid tool used by LHC experimentalists in their analyses and may well
serve as a model in other branches of science where there is a need to compare
data and complex simulations.Comment: 4 pages, 4 postscript figures, uses CHEP2004.cls. Presented at
Computing in High-Energy Physics (CHEP'04), Interlaken, Switzerland, 27th
September - 1st October 200
Jet Trimming
Initial state radiation, multiple interactions, and event pileup can
contaminate jets and degrade event reconstruction. Here we introduce a
procedure, jet trimming, designed to mitigate these sources of contamination in
jets initiated by light partons. This procedure is complimentary to existing
methods developed for boosted heavy particles. We find that jet trimming can
achieve significant improvements in event reconstruction, especially at high
energy/luminosity hadron colliders like the LHC.Comment: 20 pages, 11 figures, 3 tables - Minor changes to text/figure
Search for the Elusive Higgs Boson Using Jet Structure at LHC
We consider the production of a light non-standard model Higgs boson of order
100~\GEV with an associated boson at CERN Large Hadron Collider. We focus
on an interesting scenario that, the Higgs boson decays predominately into two
light scalars with mass of few GeV which sequently decay into four
gluons, i.e. . Since is much lighter than the Higgs
boson, it will be highly boosted and its decay products, the two gluons, will
move close to each other, resulting in a single jet for decay in the
detector. By using electromagnetic calorimeter-based and jet substructure
analyses, we show in two cases of different masses that it is quite
promising to extract the signal of Higgs boson out of large QCD background.Comment: 20 pages, 7 figure
Soil erosion and causative factors at Vandenberg Air Force Base, California
Areas of significant soil erosion and unvegetated road cuts were identified and mapped for Vandenberg Air Force Base. One hundred forty-two eroded areas (most greater than 1.2 ha) and 51 road cuts were identified from recent color infrared aerial photography and ground truthed to determine the severity and causes of erosion. Comparison of the present eroded condition of soils (as shown in the 1986 photography) with that in historical aerial photography indicates that most erosion on the base took place prior to 1928. However, at several sites accelerated rates of erosion and sedimentation may be occurring as soils and parent materials are eroded vertically. The most conspicuous erosion is in the northern part of the base, where severe gully, sheet, and mass movement erosion have occurred in soils and in various sedimentary rocks. Past cultivation practices, compounded by highly erodible soils prone to subsurface piping, are probably the main causes. Improper range management practices following cultivation may have also increased runoff and erosion. Aerial photography from 1986 shows that no appreciable headward erosion or gully sidewall collapse have occurred in this area since 1928
Non-global logarithms in inter-jet energy flow with kt clustering requirement
Recent work in inter-jet energy flow has identified a class of leading
logarithms previously not considered in the literature. These so-called
non-global logarithms have been shown to have significant numerical impact on
gaps-between-jets calculations at the energies of current particle colliders.
Here we calculate, at fixed order and to all orders, the effect of applying
clustering to the gluonic final state responsible for these logarithms for a
trivial colour flow 2 jet system. Such a clustering algorithm has already been
used for experimental measurements at HERA. We find that the impact of the
non-global logarithms is reduced, but not removed, when clustering is demanded,
a result which is of considerable interest for energy flow observable
calculations.Comment: 13 pages, 4 figure
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