16,164 research outputs found
Study on abundance of benthic macroinvertebrates in relation to soil texture types of sediment in three ponds
The present research was conducted to evaluate the monthly variations of macrozoobenthos of three ponds (pond 1, bottom soil is loam; pond 2, bottom soil is sandy loam; pond 3, bottom soil is silty clay loam) in relation to soil texture types of sediment. The major groups of macro-zoobenthos recorded were Chironomidae, Oligochaeta, Mollusca and Ceratopogonidae. The values of all water quality parameters such as temperature, water depth, rainfall, transparency, dissolved oxygen, pH, free CO2, NO3-N and PO4-P were found to have positive correlations in most cases, in some cases negative correlations and in few cases significant correlations. The abundance of Chironomidae was to be dominant in the pond no. 3 during the whole study period. The highest number of Oligochaeta (400 per m2) was found in pond no. 3 at depth of 150 cm and the lowest number of Oligochaeta (0 per m2) was found in pond nos. 1, 2 and 3 at both depths. The highest number of Chironomidae (1332 per m2) was found in pond no. 3 at depth of 150 cm and the lowest number of Chironomidae (444 per m2) was found in pond no. 2 at depth of 100 cm. The highest number of Ceratopogonidae (977 per m2) was found in pond no. 3 at the depth of 150 cm and the lowest number of Ceratopogonidae (178 per m2) was found in pond no. 2 at both depths. The highest number of Mollusca (1288 per m2) was found in pond no. 3 at the depth of 150 cm and the lowest number of Mollusca (222 per m2) was found in pond no. 2 at the depth of 100 cm. Satisfactory quantity of macrobenthos in the pond no. 3 at the depth of 150 cm than those of other two ponds. Between 2 depths (100 and 150 cm), the depth of 150 cm was to have highest quantity of macro-zoobenthos in all the three ponds because this depth was most favourable for macro-zoobenthos production. In pond no. 1, 2 and 3 relation of macro-benthos (no. per m2) with chemical parameters of pond bottom-soil conditions vary pond to pond which influence primary production and also influence macro-zoobenthos production (secondary production). The highest macro-zoobenthos population density was found in pond no. 3 followed by pond no. 1 and the lowest production in pond no. 2 but macro-zoobenthos production in pond no. 2 and pond no. 1 are more or less similar and macro-zoobenthos production in pond no. 3 is different and higher than those of pond nos. 1 and 2 which indicates that silty clay loam of bottom-soil is more suitable for macrozoobenthos than other soil textural classes of bottom-soil loam and sandy loam.Int. J. Agril. Res. Innov. & Tech. 7 (2): 27-35, December, 201
Measuring sparticle masses in non-universal string inspired models at the LHC
We demonstrate that some of the suggested five supergravity points for study
at the LHC could be approximately derived from perturbative string theories or
M-theory, but that charge and colour breaking minima would result. As a pilot
study, we then analyse a perturbative string model with non-universal soft
masses that are optimised in order to avoid global charge and colour breaking
minima. By combining measurements of up to six kinematic edges from squark
decay chains with data from a new kinematic variable, designed to improve
slepton mass measurements, we demonstrate that a typical LHC experiment will be
able to determine squark, slepton and neutralino masses with an accuracy
sufficient to permit an optimised model to be distinguished from a similar
standard SUGRA point. The technique thus generalizes SUSY searches at the LHC
Detecting exotic heavy leptons at the Large Hadron Collider
New almost-degenerate charged and neutral heavy leptons are a feature of a
number of theories of physics beyond the Standard Model. The prospects for
detecting these at the Large Hadron Collider using a time-of-flight technique
are considered, along with any cosmological or experimental constraints on
their masses. Based on a discovery criterion of 10 detected exotic leptons we
conclude that, with an integrated luminosity of 100 fb-1, it should be possible
to detect such leptons provided their masses are less than 950 GeV. It should
also be possible to use the angular distribution of the produced particles to
distinguish these exotic leptons from supersymmetric scalar leptons, at a
better than 90% confidence level, for masses up to 580 GeV
Exploring small extra dimensions at the Large Hadron Collider
Many models that include small extra space dimensions predict graviton states
which are well separated in mass, and which can be detected as resonances in
collider experiments. It has been shown that the ATLAS detector at the Large
Hadron Collider can identify such narrow states up to a mass of 2080 GeV in the
decay mode G->ee, using a conservative model. This work extends the study of
the ee channel over the full accessible parameter space, and shows that the
reach could extend as high as 3.5 TeV. It then discusses ways in which the
expected universal coupling of the resonance can be confirmed using other decay
modes. In particular, the mode G-> di-photons is shown to be measurable with
good precision, which would provide powerful confirmation of the graviton
hypothesis. The decays G-> mu mu, WW, ZZ and jet--jet are measurable over a
more limited range of couplings and masses. Using information from mass and
cross-section measurements, the underlying parameters can be extracted. In one
test model, the size of the extra dimension can be determined to a precision in
length of 7x10^-33 m
Isotopic variation of parity violation in atomic ytterbium
We report on measurements of atomic parity violation, made on a chain of
ytterbium isotopes with mass numbers A=170, 172, 174, and 176. In the
experiment, we optically excite the 6s2 1S0 -> 5d6s 3D1 transition in a region
of crossed electric and magnetic fields, and observe the interference between
the Stark- and weak-interaction-induced transition amplitudes, by making field
reversals that change the handedness of the coordinate system. This allows us
to determine the ratio of the weak-interaction-induced electric-dipole (E1)
transition moment and the Stark-induced E1 moment. Our measurements, which are
at the 0.5% level of accuracy for three of the four isotopes measured, allow a
definitive observation of the isotopic variation of the weak-interaction
effects in an atom, which is found to be consistent with the prediction of the
Standard Model. In addition, our measurements provide information about an
additional Z' boson.Comment: 19 pages, 4 figures, 2 table
Phenomenology of production and decay of spinning extra-dimensional black holes at hadron colliders
We present results of CHARYBDIS2, a new Monte Carlo simulation of black hole
production and decay at hadron colliders in theories with large extra
dimensions and TeV-scale gravity. The main new feature of CHARYBDIS2 is a full
treatment of the spin-down phase of the decay process using the angular and
energy distributions of the associated Hawking radiation. Also included are
improved modelling of the loss of angular momentum and energy in the production
process as well as a wider range of options for the Planck-scale termination of
the decay. The new features allow us to study the effects of black hole spin
and the feasibility of its observation in such theories
P16-30. Induction of Tim-3 expression by the common gamma-chain cytokines IL-2, IL-7, IL-15 and IL-21
Coronal hard X-ray sources revisited
This paper reports on the re-analysis of solar flares in which the hard
X-rays (HXRs) come predominantly from the corona rather than from the more
usual chromospheric footpoints. All of the 26 previously analyzed event time
intervals, over 13 flares, are re-examined for consistency with a flare model
in which electrons are accelerated near the top of a magnetic loop that has a
sufficiently high density to stop most of the electrons by Coulomb collisions
before they can reach the footpoints. Of particular importance in the previous
analysis was the finding that the length of the coronal HXR source increased
with energy in the 20 - 30 keV range. However, after allowing for the
possibility that footpoint emission at the higher energies affects the inferred
length of the coronal HXR source, and using analysis techniques that suppress
the possible influence of such footpoint emission, we conclude that there is no
longer evidence that the length of the HXR coronal sources increase with
increasing energy. In fact, for the 6 flares and 12 time intervals that
satisfied our selection criteria, the loop lengths decreased on average by 1.0
+/- 0.2 arcsec between 20 and 30 keV, with a standard deviation of 3.5 arcsec.
We find strong evidence that the peak of the coronal HXR source increases in
altitude with increasing energy. For the thermal component of the emission,
this is consistent with the standard CHSKP flare model in which magnetic
reconnection in a coronal current sheet results in new hot loops being formed
at progressively higher altitudes. The explanation for the nonthermal emission
is not so clear.Comment: Accepted for publication in the Astrophysical Journal. 24 pages, 8
figure
Dynamic Interactions among Boundaries and the Expansion of Sustainable Aquaculture
Aquaculture is the fastest growing food production system in the world, generating more than half of the global seafood harvested today. These type of activities are crucial to provide key nutritional components for humanity in the future as populations worldwide are increasing and the demands for securing food resources are imperative. Multiple socio-ecological factors such as weak regulations and focus on maximizing production limit production and threaten the sustainable growth of aquaculture. We present a novel policy framework to evaluate and pursue growth in aquaculture considering four boundaries: biological productivity, environmental constraints to that productivity, policy that inhibits or promotes different kinds of aquaculture, and social preferences that determine aquaculture markets. Using a range of scenarios, we have shown that sustainable growth in aquaculture requires simultaneous consideration of all four boundaries and the potential interactions between all of these options. Our proposed conceptual framework shows that to further expand the boundaries of aquaculture production, the policy focus must remain flexible to enable the adaptation of from single-boundary approaches. Our approach takes account of the current boundaries, helping to consider the adaptive policy, which is deemed as a necessary tool for considering the dynamic interactions among boundaries, thus addressing the problem of defining the evolving limits of sustainable aquaculture
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