223 research outputs found
The effect of feed made from fish processing waste silage on the growth of rainbow trout (Oncorhynchus mykiss)
This study researched the degree to which the growth of rainbow trout (Oncorhynchus mykiss) was influenced by pellet feed made from silage produced from waste generated by the fish food processing industry. During the 90 day trial, a completely random parcel method was used with three repetitions. The average weight of the rainbow trout was 54.05±235 g, while their average length was 17.46±0.11 cm. One hundred (100) trout were stocked (25 kg/m3) in each fiberglass fish feeding tank. Four different experimental groups were formed; feed without silage (control) and pellets with 25, 50 and 100% silage. Fish were fed twice per a day until they were satisfied (ad libitum). At the end of the study, the group that was fed with feed made from 50% silage increased the most in weight, followed by the control group and the groups fed with 25 and 100% silage, respectively. The average weight differences between the groups were found to be significant (P<0.05). In conclusion, it can be said that replacing the fish meal in food used to feed trout with 50% fish silage has a positive effect on growth, and that silage can be used in trout food at the aforementioned ratio.Key words: Fish meal, fish silage, growth, feed efficiency, rainbow trout
Temperature dependence of electrical properties in In/Cu2ZnSnTe4/Si/Ag diodes
WOS: 000458625200001Cu2ZnSnTe4 (CZTTe) thin films with In metal contact were deposited by thermal evaporation on monocrystalline n-type Si wafers with Ag ohmic contact to investigate the device characteristics of an In/CZTTe/Si/Ag diode. The variation in electrical characteristics of the diode was analysed by carrying out current-voltage (I-V) measurements in the temperature range of 220-360 K. The forward bias I-V behaviour was modelled according to the thermionic emission (TE) theory to obtain main diode parameters. In addition, the experimental data were detailed by taking into account the presence of an interfacial layer and possible dominant current transport mechanisms were studied under analysis of ideality factor, n. Strong effects of temperature were observed on zero-bias barrier height (Phi(B0)) and n values due to barrier height inhomogeneity at the interface. The anomaly observed in the analysis of TE was modelled by Gaussian distribution (GD) of barrier heights with 0.844 eV mean barrier height and 0.132 V standard deviation. According to the Tung's theoretical approach, a linear correlation between Phi(B0) and n cannot be satisfied, and thus the modified Richardson plot was used to determine Richardson constant (A*). As a result, A* was calculated approximately as 120.6 A cm(-2) K-2 very close to the theoretical value for n-Si. In addition, the effects of series resistance (R-s) by estimating from Cheng's function and density of surface states (N-ss) by taking the bias dependence of effective barrier height, were discussed
Massive Gravity Theories and limits of Ghost-free Bigravity models
We construct a class of theories which extend New Massive Gravity to higher
orders in curvature in any dimension. The lagrangians arise as limits of a new
class of bimetric theories of Lovelock gravity, which are unitary theories free
from the Boulware-Deser ghost. These Lovelock bigravity models represent the
most general non-chiral ghost-free theories of an interacting massless and
massive spin-two field in any dimension. The scaling limit is taken in such a
way that unitarity is explicitly broken, but the Boulware-Deser ghost remains
absent. This automatically implies the existence of a holographic -theorem
for these theories. We also show that the Born-Infeld extension of New Massive
Gravity falls into our class of models demonstrating that this theory is also
free of the Boulware-Deser ghost. These results extend existing connections
between New Massive Gravity, bigravity theories, Galileon theories and
holographic -theorems.Comment: 11+5 page
Hamiltonian analysis of BHT massive gravity
We study the Hamiltonian structure of the Bergshoeff-Hohm-Townsend (BHT)
massive gravity with a cosmological constant. In the space of coupling
constants , our canonical analysis reveals the special role of
the condition . In this sector, the dimension of the
physical phase space is found to be , which corresponds to two
Lagrangian degree of freedom. When applied to the AdS asymptotic region, the
canonical approach yields the conserved charges of the BTZ black hole, and
central charges of the asymptotic symmetry algebra.Comment: LATEX, 21 pages; v2: minor correction
Extra gauge symmetries in BHT gravity
We study the canonical structure of the Bergshoeff-Hohm-Townsend massive
gravity, linearized around a maximally symmetric background. At the critical
point in the space of parameters, defined by , we discover an
extra gauge symmetry, which reflects the existence of the partially massless
mode. The number of the Lagrangian degrees of freedom is found to be 1. We show
that the canonical structure of the theory at the critical point is unstable
under linearization.Comment: LATEX, 12 page
Tricritical gravity waves in the four-dimensional generalized massive gravity
We construct a generalized massive gravity by combining quadratic curvature
gravity with the Chern-Simons term in four dimensions. This may be a candidate
for the parity-odd tricritical gravity theory. Considering the AdS vacuum
solution, we derive the linearized Einstein equation, which is not similar to
that of the three dimensional (3D) generalized massive gravity. When a
perturbed metric tensor is chosen to be the Kerr-Schild form, the linearized
equation reduces to a single massive scalar equation. At the tricritical points
where two masses are equal to -1 and 2, we obtain a log-square wave solution to
the massive scalar equation. This is compared to the 3D tricritical generalized
massive gravity whose dual is a rank-3 logarithmic conformal field theory.Comment: 17 pages, 1 figure, version to appear in EPJ
Nonlinear Dynamics of Parity-Even Tricritical Gravity in Three and Four Dimensions
Recently proposed "multicritical" higher-derivative gravities in Anti de
Sitter space carry logarithmic representations of the Anti de Sitter isometry
group. While generically non-unitary already at the quadratic, free-theory
level, in special cases these theories admit a unitary subspace. The simplest
example of such behavior is "tricritical" gravity. In this paper, we extend the
study of parity-even tricritical gravity in d = 3, 4 to the first nonlinear
order. We show that the would-be unitary subspace suffers from a linearization
instability and is absent in the full non-linear theory.Comment: 22 pages; v2: references added, published versio
Holographic Renormalization and Stress Tensors in New Massive Gravity
We obtain holographically renormalized boundary stress tensors with the
emphasis on a special point in the parameter space of three dimensional new
massive gravity, using the so-called Fefferman-Graham coordinates with relevant
counter terms. Through the linearized equations of motion with a standard
prescription, we also obtain correlators among these stress tensors. We argue
that the self-consistency of holographic renormalization determines counter
terms up to unphysical ambiguities. Using these renormalized stress tensors in
Fefferman-Graham coordinates, we obtain the central charges of dual CFT, and
mass and angular momentum of some black hole solutions. These results are
consistent with the previous ones obtained by other methods. In this study on
the Fefferman-Graham expansion of new massive gravity, some aspects of higher
curvature gravity are revealed.Comment: Version accepted for publication in JHEP, conclusion revised,
references adde
Holographic two-point functions for 4d log-gravity
We compute holographic one- and two-point functions of critical
higher-curvature gravity in four dimensions. The two most important operators
are the stress tensor and its logarithmic partner, sourced by ordinary massless
and by logarithmic non-normalisable gravitons, respectively. In addition, the
logarithmic gravitons source two ordinary operators, one with spin-one and one
with spin-zero. The one-point function of the stress tensor vanishes for all
Einstein solutions, but has a non-zero contribution from logarithmic gravitons.
The two-point functions of all operators match the expectations from a
three-dimensional logarithmic conformal field theory.Comment: 35 pages; v2: typos corrected, added reference; v3: shorter
introduction, minor changes in the text in section 3, added reference;
published versio
Noncritical Einstein-Weyl Gravity and the AdS/CFT Correspondence
We explore four-dimensional Einstein-Weyl gravity and supergravity on anti-de
Sitter spacetime. For a specific range of the coupling with appropriate
boundary conditions, we show the effective equivalence of the theory with
Einstein gravity and AdS supergravity at the quadratic Lagrangian level.
Furthermore we show that these equivalences can be promoted to the full
nonlinear level. We also show that the similar behavior holds for the
generalized Gibbons-Hawking terms. From this we find that the correlation
functions in the dual conformal field theory of Einstein-Weyl gravity and
supergravity can be readily read off from corresponding ones from Einstein
gravity and AdS supergravity. We also give comments on some issues in critical
gravity and supergravity as well as conformal gravity and supergravity.Comment: 20 pages, 1 figure: v2, references and footnote added, typos
correcte
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