2,038 research outputs found
The effects of endosulfan on P450 1A gene expression, antioxidant enzymes activity and histopathological alterations in liver of Persian sturgeon (Acipenser persicus Borodin, 1987)
The effects of 14 days exposure to sublethal concentrations of endosulfan (10 and 40 μg L−1) were investigated in mRNA- P450 1A expression, antioxidant enzymes (SOD and CAT) activity and histopathological alterations of Persian sturgeon (Acipenser persicus) fingerlings with weights of 3–5 g. The results illustrated that the relative mRNA- P450 1A expression level significantly increased (P < 0.05) compared to the control group. Highest significant increase (P < 0.05) was observed on the first day, then decreased towards day 14 of exposure. The SOD and CAT activity showed a significant increase in fish exposed to different concentrations up to day 7, then activity decreased on day 14 in fish of all treated groups. Although signs of tissue lesions were observed on day 4, they increased from day 7 and reached the highest level on day 14. The magnitude of all changed studied parameters (gene expression, enzymes and histopathological) follows a concentration-dependent manner. © 2016 Blackwell Verlag Gmb
On Rigidity of 3d Asymptotic Symmetry Algebras
We study rigidity and stability of infinite dimensional algebras which are
not subject to the Hochschild-Serre factorization theorem. In particular, we
consider algebras appearing as asymptotic symmetries of three dimensional
spacetimes, the BMS3, u(1) Kac-Moody and Virasoro algebras. We construct and
classify the family of algebras which appear as deformations of BMS3, u(1)
Kac-Moody and their central extensions by direct computations and also by
cohomological analysis. The Virasoro algebra appears as a specific member in
this family of rigid algebras; for this case stabilization procedure is inverse
of the In\"on\"u-Wigner contraction relating Virasoro to BMS3 algebra. We
comment on the physical meaning of deformation and stabilization of these
algebras and relevance of the family of rigid algebras we obtainComment: 50 pages, one figure and two tables; v2: minor improvements,
references adde
Shadow-free multimers as extreme-performance meta-atoms
We generalize the concept of parity-time symmetric structures with the goal
to create meta-atoms exhibiting extraordinary abilities to overcome the
presumed limitations in the scattering of overall lossless particles, such as
non-zero forward scattering and the equality of scattering and extinction
powers for all lossless particles. Although the forward scattering amplitude
and the extinction cross section of our proposed meta-atoms vanish, they
scatter incident energy into other directions, with controllable
directionality. These meta-atoms possess extreme electromagnetic properties not
achievable for passive scatterers. As an example, we study meta-atoms
consisting of two or three small dipole scatters. We consider possible
microwave realizations in the form of short dipole antennas loaded by lumped
elements. The proposed meta-atom empowers extraordinary response of a
shadow-free scatterer and theoretically enables most unusual material
properties when used as a building block of an artificial medium.Comment: 14 pages, 9 Figure
Anthropogenic and Natural Influences on Soil Organic Carbon Fractions: A Case Study on Soils of Meyghan Lake in Arak, Iran
Monitoring and assessment of soil organic carbon (SOC) in the soils of arid areas are very important. The objectives of the study were to evaluate the responses of extractable and particulate organic matter in soils around Meyghan Lake in Arak (Iran) to surface water-inflows. Two layers (0-30 cm and 30-60 cm) of soils were sampled in the release sites of municipal wastewater and 3 rivers. Different fractions of SOC were measured and statistically analyzed. The soil sampled from the release sites of municipal wastewater had the highest total organic carbon (14.1 mg TOC g-1 topsoil) and free particulate organic matter (8.07 mg FPOM g-1 topsoil) due to better soil condition for plant growth. In contrast, the soil sampled from the release sites of wastewater of sodium sulfate plant had the lowest the total organic carbon (3.50 mg TOC g-1 topsoil) and all of the fractions. The cold water extractable OC (CWEOC), occluded particulate organic matter (OPOM) and the heavy fraction (HF) as slow fractions responded to soil sampling time better than active fractions. They significantly increased in the soils sampled in fall. The means of CWEOC, hot water extractable OC (HWEOC) and OPOM were higher in the soils sampled from the eastern part of the lake with higher clay and moisture contents and lower elevation. They responded better to the soil properties controlling the biological activity and biodegradation. The best fraction for the study of short-term changes of SOM by anthropogenic and natural effects was FPOM in these non-agricultural lands
Multi-critical multi-field models: a CFT approach to the leading order
We present some general results for the multi-critical multi-field models in
d>2 recently obtained using CFT and Schwinger-Dyson methods at perturbative
level without assuming any symmetry. Results in the leading non trivial order
are derived consistently for several conformal data in full agreement with
functional perturbative RG methods. Mechanisms like emergent (possibly
approximate) symmetries can be naturally investigated in this framework.Comment: 12 pages, 1 figure, Contribution to the Conference QFT2018, Quantum
Fields From Fundamental Concepts to Phenomenological Questions, Mainz 26-28
September 201
Bone mineral density in Iranian patients: Effects of age, sex, and body mass index
Introduction: Osteoporosis is a multifactorial skeletal disease that is characterized by reduced bone mineral density (BMD). BMD values de-pend on several factors such as age, sex and age at menopause. The purpose of this study was to determine the prevalence and changes in bone mineral density in Iranian patients. Meth-ods: Three hundred patients were selected through random sampling technique in 2009. BMD was assessed by Norland (Excell) technique at the lumbar and femoral neck. Weight and height were measured through standard methods. A thorough history was taken from each patient. The data was analyzed using SPSS software version 13.0. P-values less than 0.05 were con-sidered statistically significant. Results: From among the 300 studied patients, 86.6% were fe-male. their mean age was 52.7 years. Their av-erage body mass index (BMI) was 28.14 kg/m2. Mean T-Score at lumbar spine and femoral neck was −1.07 ± 1.19 and −1.75 ± 1.33 respectively. Mean BMD value at lumbar spine and femoral neck was 0.92 ± 0.19 and 0.77 ± 0.16 respectively. The prevalence of osteoporosis at lumbar spine and femoral neck was 33.7% and 16.7, respec-tively. There was a significant correlation be-tween age, BMI and BMD values (P-Value < 0.01). Correlation between gender and BMD value at the lumbar spine and femoral neck was not sig-nificant. Conclusion: This study shows that age- ing and low BMI are risk factors associated with bone loss. it is recommended to measure BMD and implement prevention programs for high- risk people.
Keywords: Bone Mineral Density; Body Mass Index;Age; Gende
Taguchi parametric study on the radial and tangential cutting forces in Dry High Speed Machining (DHSM)
In this paper, L8 Taguchi array is applied to find the most important parameters effects on the radial and tangential cutting forces of a Ti–6Al-4V ELI titanium alloy in dry high speed machining (DHSM). The experiments are performed in four cutting speeds of 150, 200, 250, and 300 m/min and two feed rates of 0.03 and 0.06 mm/rev. Also, two cutting tools in types of XOMX090308TR-ME06 of uncoated (H25) and TiAlN+TiN coated (F40M) are used. Results confirm that to minimize the resultant cutting force and radial cutting force, utilizing the lower feed rate and higher cutting speeds were considered as the best levels of factors to reach to its goal
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