7,492 research outputs found
Chain configurations in light nuclei
The model of nuclear matter built from alpha-particles is proposed. The
strong deformed shape for doubly even N=Z nuclides from carbon to magnesium has
been determined according to this model. In this paper we undertake very simple
approach, which assumes the existence of low lying chain configurations.Comment: 6 pages, 5 figure
Creation of a brane world with Gauss-Bonnet term
We study a creation of a brane world using an instanton solution. We analyze
a brane model with a Gauss-Bonnet term in a bulk spacetime. The curvature of
3-brane is assumed to be closed, flat, or open. We construct instanton
solutions with branes for those models, and calculate the value of the actions
to discuss an initial state of a brane universe.Comment: 9 pages, 10 figure
Cug2 is essential for normal mitotic control and CNS development in zebrafish.
Background:
We recently identified a novel oncogene, Cancer-upregulated gene 2 (CUG2), which is essential for kinetochore formation and promotes tumorigenesis in mammalian cells. However, the in vivo function of CUG2 has not been studied in animal models.
Results:
To study the function of CUG2 in vivo, we isolated a zebrafish homologue that is expressed specifically in the proliferating cells of the central nervous system (CNS). Morpholino-mediated knockdown of cug2 resulted in apoptosis throughout the CNS and the development of neurodegenerative phenotypes. In addition, cug2-deficient embryos contained mitotically arrested cells displaying abnormal spindle formation and chromosome misalignment in the neural plate.
Conclusions:
Therefore, our findings suggest that Cug2 is required for normal mitosis during early neurogenesis and has functions in neuronal cell maintenance, thus demonstrating that the cug2 deficient embryos may provide a model system for human neurodegenerative disorders
Artificial Immune System based on Hybrid and External Memory for Mathematical Function Optimization
Artificial immune system (AIS) is one of the natureinspired
algorithm for optimization problem. In AIS, clonal
selection algorithm (CSA) is able to improve global searching ability. However, the CSA convergence and accuracy can be further improved because the hypermutation in CSA itself cannot always guarantee a better solution. Alternatively, Genetic Algorithms (GAs) and Particle Swarm Optimization (PSO) have been used efficiently in solving complex optimization problems, but they have a tendency to converge prematurely. Thus, a hybrid PSO-AIS and a new external memory CSA based scheme called EMCSA are proposed. In hybrid PSO-AIS, the good features of PSO and AIS are combined in order to reduce any limitation. Alternatively, EMCSA captures all the best antibodies into the memory in order to enhance global searching capability. In this preliminary study, the results show that the performance
of hybrid PSO-AIS compares favourably with other algorithms
while EMCSA produced moderate results in most of the simulations
Artificial Immune System Based Remainder Method for Multimodal Mathematical Function Optimization
Artificial immune system (AIS) is one of the nature-inspired algorithm for solving optimization problems. In AIS, clonal selection algorithm (CSA) is able to improve global searching ability compare to other meta-heuristic methods. However, the CSA rate of convergence and accuracy can be further improved as the hypermutation in CSA itself cannot always guarantee a better solution. Conversely, Genetic Algorithms (GAs) and Particle Swarm Optimization (PSO) have been used efficiently in solving complex optimization problems, but they have an inclination to converge prematurely. In this work, the CSA is modified using the best solutions for each exposure (iteration) namely Single Best Remainder (SBR) - CSA. Simulation results show that the proposed algorithm is able to enhance the performance of the conventional CSA in terms of accuracy and stability for single objective functions
Antibody Remainder Method Based Artificial Immune System for Mathematical Function Optimization
Artificial immune system (AIS) is one of the natureinspired
algorithm for solving optimization problem. In AIS, clonal selection algorithm (CSA) is able to improve global searching ability. However, the CSA convergence and accuracy
can be improved further because the hypermutation in CSA
itself cannot always guarantee a better solution. Alternatively,Genetic Algorithms (GAs) and Particle Swarm Optimization(PSO) have been used efficiently in solving complex optimization problems, but they have a tendency to converge prematurely. In this study, the CSA is modified using the best solution for each exposure (iteration) namely Single Best Remainder (SBR) CSA. In this study, the results show that the performance of the proposed algorithm (SBR-CSA) compares favourably with other algorithms while Half Best Insertion (HBI) CSA produced moderate results in most of the simulations
ZERO MEAN CURVATURE SURFACES IN LORENTZ-MINKOWSKI 3-SPACE WHICH CHANGE TYPE ACROSS A LIGHT-LIKE LINE
IMMUNOSUPPRESSIVE AND GRAFT-REJECTING ANTIBODIES IN HETEROLOGOUS ANTI-LYMPHOCYTIC SERUM
Skin allografts survived longer on ALS-treated, complement-deficient (C5 negative) recipients than on ALS-treated, complement-competent (C5 positive) recipients. Administration of C5-positive serum to C5-negative, ALS-treated recipients resulted in reduced graft survival. A percentage of grafts from ALS-treated, C5-positive donors was rejected when transferred to untreated syngeneic recipients; this was not observed when C5-negative, syngeneic animals served as ALS-treated donors and untreated recipients. It was concluded that ALS has graft-rejecting properties which are promoted by late acting complement components. Unlike ALS-mediated graft rejection, ALS-mediated immunosuppression appeared to be independent of the late acting complement components. The effect of ALS on the humoral response to sheep erythrocytes was examined in complement-deficient and complement-competent mice. Immune-suppression was determined by ALS treatment of C5-competent and C5-deficient mice and also by transfer of in vitro ALS-treated spleen cells from C5-negative and C5-positive donors to cyclophosphamide-treated recipients. The ability of ALS to depress the humoral response to sheep cells and to decrease immunological competence of spleen cells was the same in the presence as in the absence of C5
Thermal reaction norms and the scale of temperature variation: latitudinal vulnerability of intertidal Nacellid limpets to climate change
The thermal reaction norms of 4 closely related intertidal Nacellid limpets, Antarctic (Nacella concinna), New Zealand (Cellana ornata), Australia (C. tramoserica) and Singapore (C. radiata), were compared across environments with different temperature magnitude, variability and predictability, to test their relative vulnerability to different scales of climate warming. Lethal limits were measured alongside a newly developed metric of “duration tenacity”, which was tested at different temperatures to calculate the thermal reaction norm of limpet adductor muscle fatigue. Except in C. tramoserica which had a wide optimum range with two break points, duration tenacity did not follow a typical aerobic capacity curve but was best described by a single break point at an optimum temperature. Thermal reaction norms were shifted to warmer temperatures in warmer environments; the optimum temperature for tenacity (Topt) increased from 1.0°C (N. concinna) to 14.3°C (C. ornata) to 18.0°C (an average for the optimum range of C. tramoserica) to 27.6°C (C. radiata). The temperature limits for duration tenacity of the 4 species were most consistently correlated with both maximum sea surface temperature and summer maximum in situ habitat logger temperature. Tropical C. radiata, which lives in the least variable and most predictable environment, generally had the lowest warming tolerance and thermal safety margin (WT and TSM; respectively the thermal buffer of CTmax and Topt over habitat temperature). However, the two temperate species, C. ornata and C. tramoserica, which live in a variable and seasonally unpredictable microhabitat, had the lowest TSM relative to in situ logger temperature. N. concinna which lives in the most variable, but seasonally predictable microhabitat, generally had the highest TSMs. Intertidal animals live at the highly variable interface between terrestrial and marine biomes and even small changes in the magnitude and predictability of their environment could markedly influence their future distributions
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