947 resultados para Guerras púnicas, 268-146 a.C.


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We extend a well-known result, about the unit ball, by H. Alexander to a class of balanced domains in . Specifically: we prove that any proper holomorphic self-map of a certain type of balanced, finite-type domain in , is an automorphism. The main novelty of our proof is the use of a recent result of Opshtein on the behaviour of the iterates of holomorphic self-maps of a certain class of domains. We use Opshtein's theorem, together with the tools made available by finiteness of type, to deduce that the aforementioned map is unbranched. The monodromy theorem then delivers the result.

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Plant viruses exploit the host machinery for targeting the viral genome-movement protein complex to plasmodesmata (PD). The mechanism by which the non-structural protein m (NSm) of Groundnut bud necrosis virus (GBNV) is targeted to PD was investigated using Agrobacterium mediated transient expression of NSm and its fusion proteins in Nicotiana benthamiana. GFP:NSm formed punctuate structures that colocalized with mCherry:plasmodesmata localized protein la (PDLP la) confirming that GBNV NSm localizes to PD. Unlike in other movement proteins, the C-terminal coiled coil domain of GBNV NSm was shown to be involved in the localization of NSm to PD, as deletion of this domain resulted in the cytoplasmic localization of NSm. Treatment with Brefeldin A demonstrated the role of ER in targeting GFP NSm to PD. Furthermore, mCherry:NSm co-localized with ER-GFP (endoplasmic reticulum targeting peptide (HDEL peptide fused with GFP). Co-expression of NSm with ER-GFP showed that the ER-network was transformed into vesicles indicating that NSm interacts with ER and remodels it. Mutations in the conserved hydrophobic region of NSm (residues 130-138) did not abolish the formation of vesicles. Additionally, the conserved prolines at positions 140 and 142 were found to be essential for targeting the vesicles to the cell membrane. Further, systematic deletion of amino acid residues from N- and C-terminus demonstrated that N-terminal 203 amino acids are dispensable for the vesicle formation. On the other hand, the C-terminal coiled coil domain when expressed alone could also form vesicles. These results suggest that GBNV NSm remodels the ER network by forming vesicles via its interaction through the C-terminal coiled coil domain. Interestingly, NSm interacts with NP in vitro and coexpression of these two proteins in planta resulted in the relocalization of NP to PD and this relocalization was abolished when the N-terminal unfolded region of NSm was deleted. Thus, the NSm interacts with NP via its N-terminal unfolded region and the NSm-NP complex could in turn interact with the ER membrane via the C-terminal coiled coil domain of NSm to form vesicles that are targeted to PD and there by assist the cell to cell movement of the viral genome complex. (C) 2015 Elsevier Inc. All rights reserved.

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Adiabatic shear localization is a mode of failure that occurs in dynamic loading. It is characterized by thermal softening occurring over a very narrow region of a material and is usually a precursor to ductile fracture and catastrophic failure. This reference source is the first detailed study of the mechanics and modes of adiabatic shear localization in solids, and provides a systematic description of a number of aspects of adiabatic shear banding. The inclusion of the appendices which provide a quick reference section and a comprehensive collection of thermomechanical data allows rapid access and understanding of the subject and its phenomena. The concepts and techniques described in this work can usefully be applied to solve a multitude of problems encountered by those investigating fracture and damage in materials, impact dynamics, metal working and other areas. This reference book has come about in response to the pressing demand of mechanical and metallurgical engineers for a high quality summary of the knowledge gained over the last twenty years. While fulfilling this requirement, the book is also of great interest to academics and researchers into materials performance.

Table of Contents

1Introduction1
1.1What is an Adiabatic Shear Band?1
1.2The Importance of Adiabatic Shear Bands6
1.3Where Adiabatic Shear Bands Occur10
1.4Historical Aspects of Shear Bands11
1.5Adiabatic Shear Bands and Fracture Maps14
1.6Scope of the Book20
2Characteristic Aspects of Adiabatic Shear Bands24
2.1General Features24
2.2Deformed Bands27
2.3Transformed Bands28
2.4Variables Relevant to Adiabatic Shear Banding35
2.5Adiabatic Shear Bands in Non-Metals44
3Fracture and Damage Related to Adiabatic Shear Bands54
3.1Adiabatic Shear Band Induced Fracture54
3.2Microscopic Damage in Adiabatic Shear Bands57
3.3Metallurgical Implications69
3.4Effects of Stress State73
4Testing Methods76
4.1General Requirements and Remarks76
4.2Dynamic Torsion Tests80
4.3Dynamic Compression Tests91
4.4Contained Cylinder Tests95
4.5Transient Measurements98
5Constitutive Equations104
5.1Effect of Strain Rate on Stress-Strain Behaviour104
5.2Strain-Rate History Effects110
5.3Effect of Temperature on Stress-Strain Behaviour114
5.4Constitutive Equations for Non-Metals124
6Occurrence of Adiabatic Shear Bands125
6.1Empirical Criteria125
6.2One-Dimensional Equations and Linear Instability Analysis134
6.3Localization Analysis140
6.4Experimental Verification146
7Formation and Evolution of Shear Bands155
7.1Post-Instability Phenomena156
7.2Scaling and Approximations162
7.3Wave Trapping and Viscous Dissipation167
7.4The Intermediate Stage and the Formation of Adiabatic Shear Bands171
7.5Late Stage Behaviour and Post-Mortem Morphology179
7.6Adiabatic Shear Bands in Multi-Dimensional Stress States187
8Numerical Studies of Adiabatic Shear Bands194
8.1Objects, Problems and Techniques Involved in Numerical Simulations194
8.2One-Dimensional Simulation of Adiabatic Shear Banding199
8.3Simulation with Adaptive Finite Element Methods213
8.4Adiabatic Shear Bands in the Plane Strain Stress State218
9Selected Topics in Impact Dynamics229
9.1Planar Impact230
9.2Fragmentation237
9.3Penetration244
9.4Erosion255
9.5Ignition of Explosives261
9.6Explosive Welding268
10Selected Topics in Metalworking273
10.1Classification of Processes273
10.2Upsetting276
10.3Metalcutting286
10.4Blanking293
 Appendices297
AQuick Reference298
BSpecific Heat and Thermal Conductivity301
CThermal Softening and Related Temperature Dependence312
DMaterials Showing Adiabatic Shear Bands335
ESpecification of Selected Materials Showing Adiabatic Shear Bands341
FConversion Factors357
 References358
 Author Index369
 Subject Index375

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The field emission behaviour of a series of Tetrahedrally Bonded Amorphous Carbon (ta-C) films has been measured. The films were produced using a Filtered Cathodic Vacuum Arc System. The threshold field for emission and current densities achievable have been investigated as a function of sp3/sp2 bonding ratio and nitrogen content. Typical as-grown undoped ta-C films have a threshold field of order 10-15 V/μm and optimally nitrogen-doped films exhibit fields as low as 5 V/μm. The emission as a function of back contact and front surface condition has also been considered and shows that the back contact has only a minor effect on emission efficiency. However, after etching in either an oxygen or hydrogen plasma, the films show a marked reduction in threshold field, down to as low as 2-3 V/μm, and a marked improvement in emission site density.

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The objective of this study was to determine the effect of dietary vitamins A, D-3, E, and C on the gonad development, lipid peroxidation, and immune response of yearling rice field eel, Monopterus albus. A 6-wk feeding trial was designed according to an L-16(4(5)) orthogonal design, in which four vitamins, each at four supplementation levels, were arranged. Sixteen diets were mixed with the different vitamin levels and randomly assigned to 16 groups of fish. Increasing dietary vitamin E supplementation level significantly (P <= 0.05) increased the gonadosomatic index and lowered the serum content of malondialdehyde of rice field eel. Increasing dietary vitamin A and C levels also showed similar effect, but the differences were not statistically significant. Serum immunoglobulin M content increased significantly (P <= 0.01) as dietary vitamin C supplementation levels increased. The concentrations of calcium in bones showed significant (P <= 0.05) trend with vitamin D-3 and A supplementation levels, but the bone phosphorus content was not affected by the dietary vitamin levels.

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Previous studies have demonstrated that germinal vesicle of amphibian oocyte contains small nuclear ribonucleoprotein polypeptide C (SNRPC). In this study, a putative member of SNRPC was identified from Carassius auratus gibelio oocyte cDNA library. Its full-length cDNA has an open reading frame of 201 nt for encoding a peptide of 66 an, a short 5'-UTR of 19 nt and a long 3'-UTR of 347 nt including a polyadenylation signal and poly- (A) tail, and the deduced amino acid sequence has 47% identity with the C-terminal of the zebrafish small nuclear ribonucleoprotein polypeptide C. Western blot analysis revealed its oocyte-specific expression. Immunofluorescence localization indicated that its gene product localized to numerous nucleoli within the oocytes and showed dynamic changes with the nucleoli during oocyte maturation. RT-PCR and Western blot analysis further revealed its constant presence in the oocytes and in the embryos until hatching. The data suggested that the newly identified CagOSNRPC might be a nucleolar protein. (c) 2006 Elsevier Inc. All rights reserved.

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