2,631 research outputs found
Total organic carbon, total nitrogen and chemical characteristics of an haplic cambisol after biochar incorporation
Biochar
has
been
used
as
a
soil
conditioner
to
increase
the
soil
organic
carbon
content
and
to
improve
the
soil
chemical
characteristics.
However,
the
effect
of
biochar
on
soil
is
still
not
clear
and
the
soil
type
and
biochar
composition
should
also
play
an
important
role.
In
this
context,
the
main
objective
of
this
work
was
to
evaluate
the
effect
of
biochar
application
on
the
organic
carbon
(C)
content
and
on
chemical
characteristics
of
subtropical
Cambisol.
The
field
experiment
was
located
at
the
State
University
of
Centro
‐
Oeste
in
Irati,
Brazil,
and
the
soil
was
classified
as
an
Haplic
Cambisol
(Embrapa,
1999).
The
applied
biochar
was
composed
mainly
by
fine
residues
(
70%
<
2mm
)
of
an
eucalyptus
biochar
that
was
a
waste
of
the
local
steel
industry.
In
February
2010,
four
increasing
doses
of
biochar
were
applied
to
the
soil
(T1
‐
0
t
ha
‐
1
;
T2
‐
10
t
ha
‐
1
;
T3
‐
20
t
ha
‐
1
and
T4
‐
40
t
ha
‐
1
)
with
four
replicates.
Soil
samples
were
composed
by
three
subsamples
collected
within
each
plot.
Biochar
was
applied
on
the
soil
surface
and
thereafter
it
was
incorporated
into
a
0
‐
10
cm
soil
depth
with
an
harrow.
Soil
samples
were
collected
in
September
2011
at
four
soil
depths:
0
‐
5;
5
‐
10;
10
‐
20
and
20
‐
30
cm.
The
samples
were
air
dried
and
passed
through
a
2
mm
sieve.
Soil
C
and
nitrogen
(N)
contents
were
determined
by
dry
combustion
and
the
soil
characteristics
assessed
were:
pH
in
water,
available
P,
exchangeable
K,
Ca,
Mg
and
Al,
potential
acidity
(H
+
Al),
cation
exchange
capacity
(CEC),
effective
cation
exchange
capacity
(ECEC)
and
base
saturation
(V%)
(Tedesco
et
al.,
1995).
The
mean
values
were
compared
using
SAS
software
(Tukey
10%).
The
main
alterations
in
soil
characteristics
were
observed
in
the
superficial
depth
(0
‐
5
cm)
(Table
1)
probably
due
to
the
permanence
of
the
biochar
fine
particles
at
the
soil
surface.
In
this
layer,
the
application
of
40
t
ha
‐
1
of
biochar
(treatment
T4)
increased
in
15.5
g
kg
‐
1
the
C
content
in
comparison
to
treatment
T1.
The
treatments
T2
and
T3
also
increased
the
C
content,
but
the
differences
were
not
significant.
N
content
was
not
affected
by
biochar
application.
The
highest
dose
of
biochar
(treatment
T4)
promoted
an
increase
of
the
C/N
ratio
from
12
to
16
at
the
0
‐
5
cm
depth.
Treatment
T4
also
increased
the
soil
pH
value
in
comparison
to
treatment
T1.
In
addition,
the
contents
of
available
P,
exchangeable
K
and
Ca
where
higher
under
treatment
T4
in
comparison
to
treatment
T1
(Table
1).
In
opposition,
exchangeable
Mg
content,
Al+H,
V%
and
CEC
were
not
altered
by
any
treatment,
but
T4
increased
the
ECEC
in
3.1
cmol
c
dm
‐
3
in
comparison
to
T1.
The
results
observed
are
probably
due
the
high
C
and
ash
(26,5%)
contents
of
biochar.
A
contribution
of
the
functional
groups
on
the
surface
of
the
biochar
to
the
ECEC
should
not
be
excluded
(Sparkes
&
Stoutjesdijk,
2011).
Our
results
indicate
that
after
two
years
of
biochar
application
an
increase
of
soil
organic
carbon
and
a
positive
impact
on
the
soil
chemical
characteristics
at
the
soil
surface
were
attained,
but
only
with
the
highest
tested
dose
(40
t
ha
‐
1
)
.Peer reviewe
Search for CP violation in D0 and D+ decays
A high statistics sample of photoproduced charm particles from the FOCUS
(E831) experiment at Fermilab has been used to search for CP violation in the
Cabibbo suppressed decay modes D+ to K-K+pi+, D0 to K-K+ and D0 to pi-pi+. We
have measured the following CP asymmetry parameters: A_CP(K-K+pi+) = +0.006 +/-
0.011 +/- 0.005, A_CP(K-K+) = -0.001 +/- 0.022 +/- 0.015 and A_CP(pi-pi+) =
+0.048 +/- 0.039 +/- 0.025 where the first error is statistical and the second
error is systematic. These asymmetries are consistent with zero with smaller
errors than previous measurements.Comment: 12 pages, 4 figure
A Study of D0 --> K0(S) K0(S) X Decay Channels
Using data from the FOCUS experiment (FNAL-E831), we report on the decay of
mesons into final states containing more than one . We present
evidence for two Cabibbo favored decay modes, and
, and measure their combined branching fraction
relative to to be = 0.0106
0.0019 0.0010. Further, we report new measurements of
=
0.0179 0.0027 0.0026, = 0.0144 0.0032 0.0016,
and = 0.0208 0.0035 0.0021 where the first error is
statistical and the second is systematic.Comment: 11 pages, 3 figures, typos correcte
Highlights from the Pierre Auger Observatory
The Pierre Auger Observatory is the world's largest cosmic ray observatory.
Our current exposure reaches nearly 40,000 km str and provides us with an
unprecedented quality data set. The performance and stability of the detectors
and their enhancements are described. Data analyses have led to a number of
major breakthroughs. Among these we discuss the energy spectrum and the
searches for large-scale anisotropies. We present analyses of our X
data and show how it can be interpreted in terms of mass composition. We also
describe some new analyses that extract mass sensitive parameters from the 100%
duty cycle SD data. A coherent interpretation of all these recent results opens
new directions. The consequences regarding the cosmic ray composition and the
properties of UHECR sources are briefly discussed.Comment: 9 pages, 12 figures, talk given at the 33rd International Cosmic Ray
Conference, Rio de Janeiro 201
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory
Atmospheric parameters, such as pressure (P), temperature (T) and density,
affect the development of extensive air showers initiated by energetic cosmic
rays. We have studied the impact of atmospheric variations on extensive air
showers by means of the surface detector of the Pierre Auger Observatory. The
rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find
that the observed behaviour is explained by a model including the effects
associated with the variations of pressure and density. The former affects the
longitudinal development of air showers while the latter influences the Moliere
radius and hence the lateral distribution of the shower particles. The model is
validated with full simulations of extensive air showers using atmospheric
profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle
Physic
Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using √s=8 TeV proton-proton collision data
A search for squarks and gluinos in final states containing high-p T jets, missing transverse momentum and no electrons or muons is presented. The data were recorded in 2012 by the ATLAS experiment in s√=8 TeV proton-proton collisions at the Large Hadron Collider, with a total integrated luminosity of 20.3 fb−1. Results are interpreted in a variety of simplified and specific supersymmetry-breaking models assuming that R-parity is conserved and that the lightest neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 1330 GeV for a simplified model incorporating only a gluino and the lightest neutralino. For a simplified model involving the strong production of first- and second-generation squarks, squark masses below 850 GeV (440 GeV) are excluded for a massless lightest neutralino, assuming mass degenerate (single light-flavour) squarks. In mSUGRA/CMSSM models with tan β = 30, A 0 = −2m 0 and μ > 0, squarks and gluinos of equal mass are excluded for masses below 1700 GeV. Additional limits are set for non-universal Higgs mass models with gaugino mediation and for simplified models involving the pair production of gluinos, each decaying to a top squark and a top quark, with the top squark decaying to a charm quark and a neutralino. These limits extend the region of supersymmetric parameter space excluded by previous searches with the ATLAS detector
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
The Pierre Auger Observatory III: Other Astrophysical Observations
Astrophysical observations of ultra-high-energy cosmic rays with the Pierre
Auger ObservatoryComment: Contributions to the 32nd International Cosmic Ray Conference,
Beijing, China, August 201
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