Likelihood-based inference for a frailty-copula model based on competing risks failure time data

A competing risks phenomenon arises in industrial life tests, where multiple types of failure determine the working duration of a unit. To model dependence among marginal failure times, copula models and frailty models have been developed for competing risks failure time data. In this paper, we propose a frailty-copula model, which is a hybrid model including both a frailty term (for heterogeneity among units) and a copula function (for dependence between failure times). We focus on models that are useful to investigate the reliability of marginal failure times that are Weibull distributed. Furthermore, we develop likelihood-based inference methods based on competing risks data, including accelerated failure time models. We also develop a model-diagnostic procedure to assess the adequacy of the proposed model to a given dataset. Simulations are conducted to demonstrate the operational performance of the proposed methods, and a real dataset is analyzed for illustration. We make an R package “gammaGumbel” such that users can apply the suggested statistical methods to their data.     

Immunodeficiency with increased immunoglobulin M associated with growth hormone insufficiency

Growth hormone deficiency associated with hypogammaglobulinemia has been reported only in a few publications. Our patient was a male with recurrent episodes of infections. Serum immunoglobulin (Ig) G was extremely low although IgM concentration was much greater than the normal limit. Growth hormone responses to insulin, 1-Dopa and growth hormone-releasing hormone were low. The mean growth hormone concentration during sleep was less than the normal limit. These results are consistent with hyper-IgM immunodeficiency associated with growth hormone deficiency. The mode of transmission appears to be autosomal dominant. This combination has not been reported previously.     

Stabilisation of heterodyne receiver sensitivity with automatic polarisation control system

A low-insertion-loss automatic optical fibre polarisation control system with low driving voltage and low monitoring power has achieved stabilisation of the receiver sensitivity within the fluctuation range of less than 0.4 dB in an optical FSK heterodyne 280 Mbit/s, 141 km transmission experiment.     

Local Structure Around Cs+ Ion In Rb2 CsC60

Local structure around Cs⁺ ion in Rb₂CsC⁶⁰ has been investigated on the basis of Cs K-edge EXAFS spectrum. It has been found that Cs⁺ ions are located mainly in the octahedral site. The fraction of Cs⁺ ions in the tetrahedral and octahedral sites has been determined.     

The meiotic recombination hot spot created by the single-base substitution ade6-M26 results in remodeling of chromatin structure in fission yeast

The G -->T transversion mutation, ade6-M26, creates the heptanucleotide sequence ATGACTG, which lies close to the 5' end of the open reading frame of the ade6 gene in Schizosaccharomyces pombe. The mutation generates a meiosis-specific recombination hot spot and a binding site for the Mts1/Mts2 protein. We examined the chromatin structure at the ade6 locus in the M26 strain and compared it to that of the wild-type and hot spot-negative control M375. Micrococcal nuclease (MNase) digestion and indirect end-labeling methods were applied. In the M26 strain, we detected a new MNase-hypersensitive site at the position of the M26 mutation and no longer observed the phasing of nucleosomes seen in the wild-type and the M375 strains. Quantitative comparison of MNase sensitivity of the chromatin in premeiotic and meiotic cultures revealed a small meiotic induction of MNase hypersensitivity in the ade6 promoter region of the wild-type and M375 strains. The meiotic induction of MNase hypersensitivity was enhanced significantly in the ade6 promoter region of the M26 strain and also occurred at the M26 mutation site. The formation of the MNase-sensitive region around the heptamer sequence was abolished by the introduction of single-nucleotide substitutions in the heptamer sequence, which also abolish hot spot activity and binding of Mts1/Mts2. These data suggest that Mts1/Mts2 binding to the heptamer sequence results in a chromatin structure suitable for the recruitment of a meiosis-specific recombination function or functions.     

Neuroendocrine phenotype differentiation in a hamster lung epithelial cell line under low oxygen pressure or after transformation by diethylnitrosamine

Oxygen pressure as low as 5% in the gas phase or 87 mmHg in the liquid phase induced various neuroendocrine cell (NEC) phenotypes in more than 80% of cells of a cloned fetal Syrian hamster lung epithelial cell line (M3E3/C3). Further, cells from a number of colonies transformed in an anchorage-independent manner by diethylnitrosamine (DEN) demonstrated a NEC phenotype. Since the cell line used is of a pluripotent stem cell type, both hypoxia and DEN appear to possess a potency for NEC phenotype induction.     

Technical progresses for PVC production

This review covers recent development of PVC production technologies of the suspension polymerization process, the bulk (mass) polymerization process and the emulsion polymerization process with some historical background. The development of process for the vinyl chloride monomer (VCM) production is also explained briefly. Since the suspension process is regarded to be the most important process with its 80% share of the world total production, this review follows mainly the technology development of the suspension polymerization process. Because of the importance of hygienic problems caused by VCM, the technology development in the field of emission control is also covered.     

Accumulable optimistic fair exchange from verifiably encrypted homomorphic signatures

Let us consider a situation where a client (Alice) frequently buys a certain kind of product from a shop (Bob) (e.g., an online music service sells individual songs at the same price, and a client buys songs multiple times in a month). In this situation, Alice and Bob would like to aggregate the total transactions and pay once per month because individual payments are troublesome. Though optimistic fair exchange (OFE) has been considered in order to swap electronic items simultaneously, known OFE protocols cannot provide such aggregate function efficiently because various costs are bounded by the number of transactions in the period. In order to run this aggregation procedure efficiently, we introduce a new kind of OFE called accumulable OFE (AOFE) that allows clients to efficiently accumulate payments in each period. In AOFE, any memory costs, computational costs, and communication complexity of the payment round must be constant in terms of the number of transactions. Since a client usually has just a low power and poor memory device, these efficiencies are desirable in practice. Currently, known approaches (e.g., based on verifiably encrypted signature scheme) are not very successful for constructing AOFE. Thus, we consider a new approach based on a new cryptographic primitive called verifiably encrypted homomorphic signature scheme (VEHS). In this paper, we propose a generic construction of AOFE from VEHS and also present a concrete VEHS scheme over a composite-order bilinear group by using the dual-form signature techniques. This VEHS scheme is also of independent interest. Since we can prove the security of VEHS without random oracles, our AOFE protocol is also secure without random oracles. Finally, we implemented our AOFE protocol, and it is efficient enough for practical use.