Modified estimator of the contribution rates of population eigenvalues

Modified estimators for the contribution rates of population eigenvalues are given under an elliptically contoured distribution. These estimators decrease the bias of the classical estimator, i.e. the sample contribution rates. The improvement of the modified estimators over the classical estimator are proved theoretically in view of their risks. We also checked numerically that the drawback of the classical estimator, namely the underestimation of the dimension in principal component analysis or factor analysis, are corrected in the modification.Comment: 25 page

MAP7D2 is a brain expressing X-linked maternal imprinted gene in humans

Increasing evidence suggests imprinted genes influence mouse and human behaviors and cognitive functions. Unlike autosomal imprinted genes, X-linked imprinted genes are expressed in a sex-dependent manner because of male hemizygosity. Therefore, these genes could directly affect sex-specific brain functions and sex-biased vulnerability to psychiatric disorders such as autism1. Comparing lymphoblastoid cell lines (LCL) and peripheral blood mononuclear cells (PBMC) from healthy adult male and females, we identified MAP7 domain containing 2 (MAP7D2) as the first human X-linked imprinted gene. Both in LCL and PBMC, MAP7D2 expression was significantly suppressed in males by maternal imprinting. In each female LCL clone, MAP7D2 was expressed higher in paternally derived allele and was affected by X-chromosome inactivation. In female PBMC, however, reactivation of maternal MAP7D2 alleles was observed. MAP7D2 was expressed specifically in the brain among human tissues with unique isoforms. These results predict a crucial role of MAP7D2 for human sex-dependent neurobiological traits

Inference of Personal Attributes from Tweets Using Machine Learning

Using machine learning algorithms, including deep learning, we studied the prediction of personal attributes from the text of tweets, such as gender, occupation, and age groups. We applied word2vec to construct word vectors, which were then used to vectorize tweet blocks. The resulting tweet vectors were used as inputs for training models, and the prediction accuracy of those models was examined as a function of the dimension of the tweet vectors and the size of the tweet blacks. The results showed that the machine learning algorithms could predict the three personal attributes of interest with 60-70% accuracy.Comment: 10 pages, 5 figures, Proceedings of the 2017 IEEE Big Dat

What can we do to Attract and Retain Young People to our Company as we Find it Difficult to Attract Employees at all Levels?

Question: As the workforce ages we are finding it a challenge to recruit new employees at all levels. So our question involves what can we do to attract and retain young people to our company? We have some insight into how to attract employees but where we would like your help is how to design our work and career paths to maintain the employees

The cost of Bitcoin mining has never really increased

The Bitcoin network is burning a large amount of energy for mining. In this paper we estimate the lower bound for the global energy cost for a period of ten years from 2010, taking into account changing oil costs, improvements in hashing technologies and hashing activity. Despite a ten-billion-fold increase in hashing activity and a ten-million-fold increase in total energy consumption, we find the cost relative to the volume of transactions has not increased nor decreased since 2010. This is consistent with the perspective that, in order to keep a the Blockchain system secure from double spending attacks, the proof or work must cost a sizable fraction of the value that can be transferred through the network. We estimate that in the Bitcoin network this fraction is of the order of 1%.Comment: 16 pages, 6 figure

Contribution of Berry Curvature to Thermoelectric Effects

Within the semiclassical Boltzmann transport theory, the formula for Seebeck coefficient $S$ is derived for an isotropic two-dimensional electron gas (2DEG) system that exhibits anomalous Hall effect (AHE) and anomalous Nernst effect (ANE) originating from Berry curvature on their bands. Deviation of $S$ from the value $S_0$ estimated neglecting Berry curvarture is computed for a special case of 2DEG with Zeeman and Rashba terms. The result shows that, under certain conditions the contribution of Berry curvature to Seebeck effect could be non-negligible. Further study is needed to clarify the effect of additional contributions from mechanisms of AHE and ANE other than pure Berry curvature.Comment: Comments: 6 pages, SCES2013, accepted for publication in JPS Conf. Pro