Most optimization methods for logistic regression or maximum entropy solve the primal problem. They range from iterative scaling, coordinate descent, quasi-Newton, and truncated Newton. Less efforts have been made to solve the dual problem. In contrast, for linear support vector machines (SVM), methods have been shown to be very effective for solving the dual problem. In this paper, we apply coordinate descent methods to solve the dual form of logistic regression and maximum entropy. Interestingly, many details are different from the situation in linear SVM. We carefully study the theoretical convergence as well as numerical issues. The proposed method is shown to be faster than most state of the art methods for training logistic regression and maximum entropy.

The complete sequence of the carp mitochondrial genome of 16,575 base pairs has been determined. The carp mitochondrial genome encodes the same set of genes (13 proteins, 2 rRNAs, and 22 tRNAs) as do other vertebrate mitochondrial DNAs. Comparison of this teleostean mitochondrial genome with those of other vertebrates reveals a similar gene order and compact genomic organization. The codon usage of proteins of carp mitochondrial genome is similar to that of other vertebrates. The phylogenetic relationship for mitochondrial protein genes is more apparent than that for the mitochondrial tRNA and rRNA genes.

Branchial mitochondria-rich (MR) cells were examined on the afferent side of gill filaments in tilapia (Oreochromis mossambicus) acclimated to different hypotonic environments, local fresh water (LFW), hard fresh water (HFW) and 5‰ salt water (SW). Scanning electron micrographs (SEM) identified three types of apical surfaces of the MR cells, wavy convex, shallow basin and deep hole. In spite of the different types of apical surfaces, light microscopic (LM) and transmission electron microscopic (TEM) studies suggested that these cells were MR cells. The relative abundance of these 3 types of branchial MR cells varied with external hypotonic milieus. Wavy-convexed MR cells were dominant in the gills of fish adapted to HFW, whereas shallow-basined MR cells were evident in LFW-adapted fish. In SW-adapted fish, most of the MR cells were deep holes. Experiments on adaptation to various hypotonic milieus revealed that the changes of the branchial MR cells were reversible and occurred within 24 hours following transfer. The morphological alterations of the MR cells correlated with ionic changes in different milieus, indicating that these distinct types of MR cells may play key roles for osmoregulation in hypotonic media.

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