Belief Propagation Algorithm for Portfolio Optimization Problems

The typical behavior of optimal solutions to portfolio optimization problems with absolute deviation and expected shortfall models using replica analysis was pioneeringly estimated by S. Ciliberti et al. [Eur. Phys. B. 57, 175 (2007)]; however, they have not yet developed an approximate derivation method for finding the optimal portfolio with respect to a given return set. In this study, an approximation algorithm based on belief propagation for the portfolio optimization problem is presented using the Bethe free energy formalism, and the consistency of the numerical experimental results of the proposed algorithm with those of replica analysis is confirmed. Furthermore, the conjecture of H. Konno and H. Yamazaki, that the optimal solutions with the absolute deviation model and with the mean-variance model have the same typical behavior, is verified using replica analysis and the belief propagation algorithm.     

Effect of Weak Acid Hypochlorous Solution on Selected Viruses and Bacteria of Laboratory Rodents

Weak acid hypochlorous solution (WAHS) is known to have efficacy for inactivating pathogens and to be relatively safe with respect to the live body. Based on these advantages, many animal facilities have recently been introducing WAHS for daily cleaning of animal houses. In this study, we determined the effect of WAHS in inactivating specific pathogens of laboratory rodents and pathogens of opportunistic infection. WAHS with an actual chloride concentration of 60 ppm and a pH value of 6.0 was generated using purpose-built equipment. One volume of mouse hepatitis virus (MHV), Sendai virus, lymphocytic choriomeningitis virus, Bordetella bronchiseptica, Pasteurella pneumotropica, Corynebacterium kutscheri, Staphylococcus aureus, and Pseudomonas aeruginosa was mixed with 9 or 99 volumes of WAHS (×10 and ×100 reaction) for various periods (0.5, 1, and 5 min) at 25°C. After incubation, the remaining infectious viruses and live bacteria were determined by plaque assay or culture. In the ×100 reaction mixture, infectious viruses and live bacteria could not be detected for any of the pathogens examined even with the 0.5-min incubation. However, the effects for MHV, B. bronchiseptica, and P. aeruginosa were variable in the ×10 reaction mixture with the 0.5- and 1-min incubations. Sufficient effects were obtained by elongation of the reaction time to 5 min. In the case of MHV, reducing organic substances in the virus stock resulted in the WAHS being completely effective. WAHS is recommended for daily cleaning in animal facilities but should be used properly in order to obtain a sufficient effect, which includes such things as using a large enough volume to reduce effects of organic substances.     

In vitro inhibition and intracellular enhancement of lysosomal alpha-galactosidase A activity in Fabry lymphoblasts by 1-deoxygalactonojirimycin and its derivatives.

Fabry disease is a lysosomal storage disorder caused by deficient lysosomal alpha-galactosidase A (alpha-Gal A) activity. Deficiency of the enzyme activity results in progressive deposition of neutral glycosphingolipids with terminal alpha-galactosyl residue in vascular endothelial cells. We recently proposed a chemical chaperone therapy for this disease by administration of 1-deoxygalactonojirimycin, a potent inhibitor of the enzyme, at subinhibitory intracellular concentrations [Fan, J.-Q., Ishii, S., Asano, N. and Suzuki, Y. (1999) Nat. Med. 5, 112-115]. 1-Deoxygalactonojirimycin served as a specific chaperone for those mutant enzymes that failed to maintain their proper conformation to avoid excessive degradation. In order to establish a correlation between in vitro inhibitory activity and intracellular enhancement activity of the specific chemical chaperone, a series of 1-deoxygalactonojirimycin derivatives were tested for activity with both alpha-Gal A and Fabry lymphoblasts. 1-Deoxygalactonojirimycin was the most potent inhibitor of alpha-Gal A with an IC50 value of 0.04 microM. alpha-Galacto-homonojirimycin, alpha-allo-homonojirimycin and beta-1-C-butyl-deoxygalactonojirimycin were effective inhibitors with IC50 values of 0.21, 4.3 and 16 microM, respectively. N-Alkylation, deoxygenation at C-2 and epimerization at C-3 of 1-deoxygalactonojirimycin markedly lowered or abolished its inhibition toward alpha-Gal A. Inclusion of 1-deoxygalactonojirimycin, alpha-galacto-homonojirimycin, alpha-allo-homonojirimycin and beta-1-C-butyl-deoxygalactonojirimycin at 100 microM in culture medium of Fabry lymphoblasts increased the intracellular alpha-Gal A activity by 14-fold, 5.2-fold, 2.4-fold and 2.3-fold, respectively. Weaker inhibitors showed only a minimum enhancement effect. These results suggest that more potent inhibitors act as more effective specific chemical chaperones for the mutant enzyme, and the potent competitive inhibitors of alpha-Gal A are effective specific chemical chaperones for Fabry disease.     

Interacting effect of thermoperiod and photoperiod on the eclosion rhythm in the onion fly, Delia antiqua supports the two-oscillator model

Daily light and temperature cycles entrain adult eclosion rhythms in many insect species, but little is known about their interaction. We studied this problem in the onion fly, Delia antiqua. Pupae were subjected to various combinations of a photoperiod of 12L:12D and thermoperiods. The thermoperiods consisted of 12 h warm phase (W) and 12 h cool phase (C), giving a mean temperature of 25 °C with different temperature steps of 8, 4 and 1 °C. As the phase relation of the two Zeitgebers was varied, the phase of eclosion rhythm was shifted, depending on the phase angle with the light cycle and the amplitude of the temperature cycle. When the temperature step in the thermoperiod was 8 °C (WC 29:21 °C), the eclosion rhythm was entrained mainly to thermoperiod rather than photoperiod. In the regime with a 4 °C temperature step (WC 27:23 °C), both thermoperiod and photoperiod affected eclosion rhythm, and a phase jump of the eclosion rhythm occurred when the warm phase of thermoperiod was delayed 15-18 h from light-on. In regimes with a 1 °C temperature step (WC 25.5:24.5 °C), the eclosion rhythm was completely entrained to photoperiod. The observed interacting effect of light and temperature cycle on the eclosion rhythm in D. antiqua can be explained by the two-oscillator model proposed by Pittendrigh and Bruce (1959).     

Effect of one-legged exercise on the strength, power and endurance of the contralateral leg. A randomized, controlled study using isometric and concentric isokinetic training.

The purpose of this investigation was to study the effect of one-legged exercise on the strength, power and endurance of the contralateral leg. The performance of the knee extensor and flexor muscle of 20 healthy young adults (10 men and 10 women) was first tested by Cybex II+ and 340 dynamometers. Then 10 subjects were chosen at random to train using one leg three times a week for 7 weeks whilst the other 10 served as controls. During the 8th week, the tests were repeated. Both quadriceps and hamstring muscles of the trained subjects showed a cross-transfer effect from the trained limb to the untrained side. This concerned the strength and power, as well as endurance characteristics of these muscles. The average change in peak torque of the quadriceps muscle was +19% (P less than 0.001) in the trained limb, +11% (P less than 0.01) in the untrained limb and 0% in the control limbs. In hamstring muscles the changes were +14% (P less than 0.01), +5% and -1%, respectively. Concerning muscle endurance (work performed during the last 5 contractions in the 25-repetition test) the corresponding changes were +15% (P less than 0.01), +7% (P less than 0.01), and -1% in quadriceps muscle, and +17% (P less than 0.05), +7%, and -3% in hamstring muscles. The average strength benefit in the untrained limb was +36% (hamstring muscles) and +58% (quadriceps muscle) of that achieved in the trained limb. Untrained hamstring muscle showed better benefits in the endurance parameters than in strength or power parameters, while in the quadriceps muscle this effect was reversed. A positive relationship was observed between the changes (greater improvement in the trained limb resulted in greater improvement in the untrained limb) (hamstring muscles: r = 0.83, P less than 0.001, quadriceps muscle: r = 0.53, P less than 0.001). In endurance parameters, this relationship was almost linear while in the strength and power parameters the results were more in favour of a curvilinear relationship with limited benefit.     

Cis phosphorylated tau as the earliest detectable pathogenic conformation in Alzheimer disease,offering novel diagnostic and therapeutic strategies

After protein phosphorylation on certain serine or threonine residues preceding a proline (pSer/Thr-Pro), the function of certain phosphorylated protein is further regulated by cis-trans conformational change. Due to the lack of any tool to detect such two conformations in cells, however, it is not even known whether any cis or trans conformation exists in vivo, not to mention their conformation-specific functions or regulation. We developed a novel peptide chemistry technology to generate the first pair of antibodies that can distinguish cis from trans pThr231-Pro tau. Cis, but not trans, pThr231-tau appears early in mild cognitive impairment (MCI) neurons and further accumulates in only degenerating neurons as Alzheimer disease (AD) progresses, localizing to dystrophic neurites, which are known to correlate well with memory loss. Unlike trans p-tau, the cis cannot promote microtubule assembly, and is more resistant to dephosphorylation and degradation and more prone to aggregation. Pin1 accelerates cis to trans isomerization to prevent tau pathology in AD. Thus, during MCI and AD development, cis pThr231-Pro tau is the earliest detectable pathogenic tau conformation and antibodies and vaccines against the pathogenic cis p-tau may be used for the early diagnosis and treatment of AD. These findings offer in vivo approach to study conformational regulation of Pro-directed phosphorylation signaling.     

Ecological traits determine the affinity of birds to a larch plantation matrix,in montane Nagano,central Japan

Although the affinity to the matrix habitat (matrix affinity) determines the fate of species in dynamic landscapes where habitat replacement occurs, only a few studies have examined which ecological traits are associated with matrix affinity. Here, we examined the associations of five ecological traits (i.e., fertility, body weight, migratory behavior, foraging height, and nesting height) with affinity for forest birds to a novel larch plantation matrix habitat. We surveyed the occurrence of birds in larch plantations (matrix habitat) and original deciduous forests (original habitat) in the winter and the breeding season, in a montane region of Nagano prefecture, central Japan. We treated occurrences in the matrix habitat relative to the original habitat as the matrix affinity of each species and examined the associations of ecological traits with matrix affinity, controlling for the relatedness of species. Fertile, resident, and low-nesting species showed high matrix affinity, while an association with body weight was not supported. The associations of foraging groups with matrix affinity were complex. While early successional species showed high matrix affinity, flycatchers had low matrix affinity. The matrix affinity of some foraging groups was greater in the winter than in the breeding season. Based on the results, we predicted that low fertility and migratory, high-nesting species would be sensitive to habitat replacement due to matrix hostility. These predictions may be applicable to other matrix type, region, and taxa.     

Cessation of annual apical growth and partial death of cambium in stem of Abies sachalinensis under intensive shading

Journal of Plant Research - This study evaluated variation in the height at which absent rings and internodes were detected along stem of Abies sachalinensis trees grown under shade for...