Geometric consistency of principal component scores for high-dimensional mixture models and its application

In this article, we consider clustering based on principal component analysis (PCA) for high-dimensional mixture models. We present theoretical reasons why PCA is effective for clustering high-dimensional data. First, we derive a geometric representation of high-dimension, low-sample-size (HDLSS) data taken from a two-class mixture model. With the help of the geometric representation, we give geometric consistency properties of sample principal component scores in the HDLSS context. We develop ideas of the geometric representation and provide geometric consistency properties for multiclass mixture models. We show that PCA can cluster HDLSS data under certain conditions in a surprisingly explicit way. Finally, we demonstrate the performance of the clustering using gene expression datasets.     

Sleep disturbance as a clinical sign for severe hypogonadism: efficacy of testosterone replacement therapy on sleep disturbance among hypogonadal men without obstructive sleep apnea

Objective: The present subanalysis of the EARTH study investigates the effects of one year testosterone replacement therapy (TRT) on sleep disturbance among hypogonadal men without obstructive sleep apnea.

Methods: Sleep disturbance was defined as three or more points in question 4 of the aging males symptoms (AMS) questionnaire. All participants completed the AMS scale, International Prostatic Symptoms Score (IPSS), Sexual Health Inventory for Men (SHIM) and Short Form 36 (SF-36) health survey at baseline and after 12?months. Sexual symptoms were also evaluated based on three AMS subscores (Q15, 16 and 17).

Results: We identified 100 patients with sleep disturbance, of whom 48 (24 each in the TRT and control groups) were ultimately included for analysis. All SF-36 categories , AMS scale, IPSS and SHIM score subdomains were significantly worse in patients with sleep disturbance than in those without disturbance. Statistically significant differences in sleep disturbance, erectile symptoms, sexual desire and some domains of the SF-36 were observed between the TRT and control groups after 12?months.

Conclusion: Sleep disturbance may be one of the clinical signs for severe hypogonadism. Moreover, TRT improved sleep conditions, sexual function and quality of life among hypogonadal men with sleep disturbance.     

Effects of testosterone replacement therapy on hypogonadal men with osteopenia or osteoporosis: a subanalysis of a prospective randomized controlled study in Japan (EARTH study)

Objective: We investigated the effects of testosterone replacement therapy (TRT) on bone mineral density (BMD) among hypogonadal men with osteopenia/osteoporosis.

Methods: From our previous EARTH study population, 74 patients with a clinical diagnosis of osteopenia or osteoporosis and hypogonadism were included in this study, as the TRT (n?=?35) and control (n?=?34) groups. The TRT group was administered 250?mg of testosterone enanthate injection every 4 weeks for 12 months. The BMD, waist circumference, body mass index, body fat percentage, and muscle volume were measured at baseline and at 12 months. Blood biochemical data, including total cholesterol, triglycerides, HDL-cholesterol, hemoglobin A1c, and adiponectin values were also evaluated.

Results: At the 12-month visit, BMD significantly increased in both groups. However, comparisons on changes of parameter values from baseline to the 12-month visit between the TRT and control groups were significantly different in BMD (5.0?±?5.0 vs. 3.0?±?3.2; p?=?.0434) and in adiponectin value (?0.90?±?3.33 vs. 0.10?±?2.04; p?=?.0192). There were no significant changes in other parameters.

Conclusions: TRT for 12 months could improve BMD with a decrease in adiponectin levels among hypogonadal men with osteopenia/osteoporosis.     

The estimation of population density of the green rice leafhopper,Nephotettix cinticeps Uhler, in spring field by the capture recapture method

Summary The population parameters of green rice leafhopper,Nephotettix cincticeps in hibernated generation was estimated by the capture-recapture method on the gramineous weeds of resting paddy field from late in April to mid-May, 1962–1965. The difficulty of applying the capture-recapture method to this insect is caused from the low density and the low activity of the leafhopper, so that it is necessary to make the suitable plan of capture-recapture series and to construct the special method to detect the population parameters. The number of adults differed greatly among the years and among the plots in the same year. But, in general, the density was relatively high late in April, and decreased rapidly in May. The number of males was higher than that of females late in April, but decreased rapidly to become lower in May. The sampling efficiency with sweep-net depends upon the many factors, such as weather and floristic conditions; especially the atmospheric temperature and the force of wind are considered to affect greatly to the efficiency. In general, low temperature and strong wind are the cause of low sampling efficiency. Contribution from JIBP-PT No. 20.     

A note on the relationship between outbreaks of the oriental tussock moth,Euproctis flava and weather conditions

Summary A relationship between outbreaks of the oriental tussock moth,Euproctis flava, in Akita Prefecture and weather conditions have been analyzed in the present paper. The results obtained are summarized as follows: Outbreaks were, in most cases, observed at intervals of 7–9 years, and the population fluctuation was considered to be regular, when small rises of population density were taken into consideration. The condition of low temperature and decreased percentage of sunny hours in spring and summer has a great influence upon the occurrence of outbreaks, and a big outbreak seems to come when a peak of the intrinsic population fluctuation occurs just simultaneously with such a weather condition.     

Dispersal of adult grasshoppers,Mecostethus magister, under the field condition

Summary Estimation of the number of adult grasshoppers,Mecostethus magister, was made by means of the mark-and-recapture method. The birth and death rates are possible to be estimated at the same time, but the immigration and the emigration rate are inevitably involved in these respectively. The immigration and emigration rates must be made clear to know the true birth and death rates. For this purpose the movement of the marked males in 1963 was analyzed. The grasshoppers dominantly moved in the directions of N, NW and W, and the difference in frequency among the movement directions was not so large. The distribution of the dispersal-distance relationship of each quadrate on each released day was fitted approximately to normal distribution. It could be concluded that almost all of the grasshoppers moved within the range of about 31–35m. The emigration rate from the quadrate (12×12m²) was about 0.73–0.77 and the difference in the rate among the released days was small. From these values the emigration rate from the station (84×60m²) was estimated as 0.21–0.23. Subtracting the emigration rate from the death-and-emigration rate, the true death rate was calculated. The death rate was very low until the number of males reached to the peak, then increased gradually. Supposing that immigration rate was equal to the emigration rate, the true birth rate was also estimated. But the presumption might not be pertinent, for the value of birth rates became negative.     

Double shrink methodologies to determine the sample size via covariance structures

We consider fixed-size estimation for a linear function of mean vectors from _πi:_Np(_μi,_Σi)${\pi }_i:{\mathrm{N}}_p({\mathit{\mu }}_i,{\mathbf{\Sigma }}_i)$, i=1,…,k$i=1,\dots ,k$, when every _Σi${\mathbf{\Sigma }}_i$ has some structure. The goal of inference is to construct a fixed-span confidence region with required accuracy. We find a sample size for each _πi${\pi }_i$ with the help of the ‘double shrink methodology’, that is introduced by this paper, via covariance structures of _Σi${\mathbf{\Sigma }}_i$, i=1,…,k$i=1,\dots ,k$. We estimate the sample size in a two-stage sampling and give a fixed-span confidence region that has the coverage probability approximately second-order consistent with the required accuracy. Some simulations are carried out to see moderate sample size performances of the proposed methodologies.     

Reproductive behavior of the Japanese treefrog,Rhacophorus arboreus (Anura: Rhacophoridae)

Reproductive behavior of the foam-nesting treefrog,Rhacophorus arboreus, is described. Oviposition was made either by an amplectant pair (a female, and an amplectant male) alone or by an amplectant pair and other males (joiners). The snout-vent length of males and females was negatively correlated with the date of the first appearance in the pond. The period of staying in the pond in males was longer than that in females. Physical body contacts of other males, and encounter calls by ampletant males were frequently observed before oviposition with joiners. Snout-vent length of the female and an amplectant male were positively correlated. Encounter calls by amplectant males were likely to precede movement of females. There was no difference of snout-vent length between amplectant males and joiners. Females moved the hindlimbs more frequently than males during oviposition. Amplectant males made encounter cells more frequently in oviposition with joiners, than oviposition without joiners. The patterns of transitions between acts of females and amplectant males were similar between oviposition with and without joiners. Females more frequently responded to amplectant males than joiners. Both the duration of a bout of the movements of hindlimbs of females and the interval between the bouts were longer in oviposition without joiners than that with joiners. The number of the movements per bout in oviposition without joiners was smaller than that with joiners. Encounter calls by amplectant males during oviposition tended to precede the hindlimb movements of females.     

The correlation between highly sensitive C-reactive protein levels and erectile function among men with late-onset hypogonadism

We investigated the correlation between highly sensitive C-reactive protein (hs-CRP) levels and erectile function, and assessed the clinical role of hs-CRP levels in men with late-onset hypogonadism (LOH) syndrome. For 77 participants, we assessed Sexual Health Inventory for men (SHIM) score, Aging Male Symptoms (AMS) score and International Prostate Symptom Score (IPSS). We also evaluated free testosterone (FT), hs-CRP, total cholesterol, triglyceride levels, high density lipoprotein cholesterol, hemoglobin A1c, body mass index, waist size and blood pressure. We attempted to identify parameters correlated with SHIM score and to determine the factors affecting cardiovascular risk based on hs-CRP levels. A Spearman rank correlation test revealed that age, AMS score, IPSS and hs-CRP levels were significantly correlated with SHIM score. Age-adjusted analysis revealed that hs-CRP and IPSS were the independent factors affecting SHIM score (r=??0.304 and ?0.322, respectively). Seventeen patients belonged to the moderate to high risk group for cardiovascular disease, whereas the remaining 60 belonged to the low risk group. Age, FT value and SHIM score showed significant differences between the two groups. A multivariate regression analysis demonstrated that SHIM score was an independent factor affecting cardiovascular risk (OR: 0.796; 95%CI: 0.637–0.995).