Comparison of Ranges for Al Implantations into 4H-SiC (0001) Using Channeled Ions and an Ion Energy in the Bethe-Bloch Region

Ranges for Al implantations into 4H-SiC (0001) were compared between channeled-ion implantation (without using a MeV implanter) and non-channeled ion implantation using an ion energy E0 in the Bethe–Bloch region (IIBB). Since the latter (i.e., projected range of 7.5 μm at E0 = 26 MeV) was larger than the former (i.e., maximum channeled range of 3.4 μm at E0 = 900 keV), IIBB was concluded to be suitable to minimize the repeat count of epitaxial growth/ion implantation steps used in the fabrication of 4H-SiC superjunction power devices.

Evidence for the s count macrogene

Background: A macrogene is defined here as a gene on which successive mutations incrementing a repeat count produces successive punctuated evolutionary events in species that are homogeneous for it. The set of repeat count on the asp (abnormal spindle) family of gene is thought to affect brain size in mammals. Corticogenesis requires two integer valued (quantum) variables, the f and s counts, to determine the number of division cycles during the first and second phases, respectively, of neuron production in the cerebral cortex. Quantum ‘extra’ neuron theory hypothesizes that increments in a quantum variable, the n count, cause punctuated encephalization events in species that are homogenous for it. There is evidence in six pairs of inbred mice strains for one or more major genes affecting brain size. Results: The s count is probably equal to the n count plus a positive integer. The calculated n counts are different in three of the four pairs of strains studied where encephalization data has been previously published. Five different n counts have been found in eleven mouse strains. The difference between the n counts of humans and mice is about 25. Conclusions: Encephalization in mammals may be caused by a macrogene that determines the s count. This theory can be tested by determining the s counts of the various mice strains. However, the asp family of gene is probably not the s count macrogene because the difference in the asp counts of humans and mice of 13 (= 74 – 61) is much smaller than the difference in their s counts of around 25.

Evidence for the s count macrogene

Background: A macrogene is defined here as a gene on which successive mutations incrementing a repeat count produces successive punctuated evolutionary events in species that are homogeneous for it. The set of repeat count on the asp (abnormal spindle) family of gene is thought to affect brain size in mammals. Corticogenesis requires two integer valued (quantum) variables, the f and s counts, to determine the number of division cycles during the first and second phases, respectively, of neuron production in the cerebral cortex. Quantum ‘extra’ neuron theory hypothesizes that increments in a quantum variable, the n count, cause punctuated encephalization events in species that are homogenous for it. There is evidence in six pairs of inbred mice strains for one or more major genes affecting brain size. Results: The s count is probably equal to the n count plus a positive integer. The calculated n counts are different in three of the four pairs of strains studied where encephalization data has been previously published. Five different n counts have been found in eleven mouse strains. The difference between the n counts of humans and mice is about 25. Conclusions: Encephalization in mammals may be caused by a macrogene that determines the s count. This theory can be tested by determining the s counts of the various mice strains. However, the asp family of gene is probably not the s count macrogene because the difference in the asp counts of humans and mice of 13 (= 74 – 61) is much smaller than the difference in their s counts of around 25.

Revised population estimate and trends for the Endangered Northern Rockhopper Penguin Eudyptes moseleyi at Tristan da Cunha

Around 80% of the world population of Northern Rockhopper Penguin Eudyptes moseleyi is found at Tristan da Cunha and Gough Island in the South Atlantic Ocean, where populations appear to be declining. However, numbers of birds at Middle Island, a small satellite island of Nightingale Island at Tristan Cunha, have not been counted since 1973 when an estimated 100,000 pairs were recorded. Updated population counts were obtained for all four islands at Tristan da Cunha (Tristan, Inaccessible, Nightingale and Middle islands) in 2009 providing a census of the whole island group and the first repeat count of Middle Island. Estimated breeding numbers at these four islands were Tristan 6,700 pairs, Inaccessible 54,000 pairs, Nightingale 25,000 pairs and 83,000 pairs at Middle Island. These counts confirm that Tristan da Cunha is a vitally important site for this ?Endangered? species holding over 65% of the global population and that breeding number have been relatively stable over the last 30 years.

Evidence for Complex Mutations at Microsatellite Loci in Drosophila

Fifteen lines each of Drosophila melanogaster, D. simulans, and D. sechellia were scored for 19 microsatellite loci. One to four alleles of each locus in each species were sequenced, and microsatellite variability was compared with sequence structure. Only 7 loci had their size variation among species consistent with the occurrence of strictly stepwise mutations in the repeat array, the others showing extensive variability in the flanking region compared to that within the microsatellite itself. Polymorphisms apparently resulting from complex nonstepwise mutations involving the microsatellite were also observed, both within and between species. Maximum number of perfect repeats and variance of repeat count were found to be strongly correlated in microsatellites showing an apparently stepwise mutation pattern. These data indicate that many microsatellite mutation events are more complex than represented even by generalized stepwise mutation models. Care should therefore be taken in inferring population or phylogenetic relationships from microsatellite size data alone. The analysis also indicates, however, that evaluation of sequence structure may allow selection of microsatellites that more closely match the assumptions of stepwise models.

A Performance Analysis of Compressed Compact Genetic Algorithm

Compressed compact genetic algorithm (c2GA) is an algorithm that utilizes the compressed chromosome encoding and compact genetic algorithm (cGA). The advantage of c2GA is to reduce the memory usage by representing population as a probability vector. In this paper, we analyze the performance in term of robustness of c2GA. Since the compression and decompression strategy employ two parameters, which are the length of repeating value and the repeat count, we vary these two parameters to see the performance affected in term of convergence speed. The experimental results show that c2GA outperforms cGA and is a robust algorithm.