Analyses of the coupling between large-scale atmospheric patterns and modifications of regional precipitation regimes at seasonal and annual time scales in different terrain of mid-latitudes in Asia, including western Siberia, Tien Shan and Pamir mountains, and plains of middle Asia and Japanese Islands, were examined based on data from 57 and 88 hydro-climatic stations with 100 and 60 year records, respectively. For the past 100 years, a positive trend in precipitation was revealed in western Siberia, northern regions of Tien Shan and Japanese Islands. North Atlantic Oscillation (NAO) and West Pacific Oscillation (WPO) indices have inverse associations, with average amount of precipitation in western Siberia and in mountains and plains of middle Asia, and positive correlation in central and western regions of Japanese Islands. The Pacific North American (PNA) index is positively correlated with annual precipitation over most of the Japanese Islands. Northern Asian (NA) positive anomalies lead to decrease in winter precipitation in the western and eastern regions of Japanese Islands. We did not find significant impact of PNA or NA on precipitation in middle Asia. We suggest that during the last century, impacts of the western jet stream increased in the northern regions of Tien Shan and Japanese Islands, and weakened in the eastern Japanese Islands. There is a suggestion that conditions are more favourable for precipitation development over continental regions of Asia when the Siberian High is positioned further to the east than further to the west. During dominant development of a zonal atmospheric pattern, the annual and seasonal precipitation decreased over most regions in continental Asia and central Japan.
To understand the effects of climate change on the growing season of plants in Japan, we conducted trend analysis of phenological phases and examined the relationship between phenology and air temperatures. We used phenological data for Ginkgo biloba L., collected from 1953 to 2000. We defined the beginning and the end of the growing season (BGS and EGS) as the dates of budding and leaf fall, respectively. Changes in the air temperature in the 45 days before the date of BGS affected annual variation in BGS. The annual variation in air temperature over the 85 days before EGS affected the date of EGS. The average annual air temperature in Japan has increased by 1.3°C over the last four decades (1961–2000), and this increase has caused changes in ginkgo phenology. In the last five decades (1953–2000), BGS has occurred approximately 4 days earlier than previously, and EGS has occurred about 8 days later. Consequently, since 1953 the length of the growing season (LGS) has been extended by 12 days. Since around 1970, LGS and air temperatures have shown increasing trends. Although many researchers have stated that phenological events are not affected by the air temperature in the fall, we found high correlations not only between budding dates and air temperatures in spring but also between leaf‐fall dates and air temperatures in autumn. If the mean annual air temperature increases by 1°C, LGS could be extended by 10 days. We also examined the spatial distribution of the rate of LGS extension, but we did not find an obvious relationship between LGS extension and latitude.
Androgens are well known for their many functions in promoting sexual differentiation and the induction of the male phenotype. In the male, the two endogenous androgens most active in promoting these effects are testosterone and nonaromatizable 5a-dihydrotestosterone (DHT). They also play important roles in the regulation of bone metabolism. The direct effects of androgen on bone cells is suggested by the presence of androgen receptors (AR) on several human and rat established osteoblast cell lines as well as normal human osteoblast cells (HOB).1) Androgens increase rates of cellular proliferation and differentiation of osteoblasts, increase TGF-b levels, increase production of matrix proteins and inhibit osteoclast function.2,3) A role of androgens in skeletal regulation is substantiated by numerous studies in human and rodents, demonstrating that chemical or surgical castration, as well as untreated hypogonadism in men and androgen deficiency in women with hypopituitarism, lead to accelerated bone loss.2,4-7) Importantly, the deleterious effects of these conditions on bone can be reversed by treatment with androgens.One apparently unique effect of androgens is to increase periosteal bone formation in cortical bone, while estrogens depress it.8) This reflects a major gender difference in bone size, which is one of important factors determining the bone strength. A number of studies provide the proof of principle that androgens are osteoanabolic in rodents, women and men. Nonaromatizable DHT increased cortical bone volume and periosteal bone formation rates when administrated to ovariectomized rats.9) The synthetic anabolic steroids, such as nandrolone decanoate or stanozolol, have been shown to increase bone mass in postmenopausal women, possibly via stimulation of bone formation.10,11) Beneficial anabolic effects of androgens on bone in postmenopausal osteoporosis are well-documented in recent studies using combined testosterone and estrogen administration.12,13) On the other hand, bone resorption inhibitors such as estrogens, bisphosphonates, selective estrogen receptor modulators (SERMs) and calcitonin, which are still first line of treatment/prevention of osteoporosis, are not sufficient to restore bone mass for patients who have already lost a significant amount of bone. In addition, bone turnover rate differs from site to site; higher in the cancellous bone of vertebrae than in the cortical bone of the long bones. Therefore, osteoanabolic agents, which increase cortical/periosteal bone formation and bone mass of long bones, would address unmet need in the treatment of osteoporosis especially for patients with high risk of fractures. The osteoanabolic agents also complement the bone resorption inhibitors that target the cancellous bones, leading to a biomechanically favorable bone structure. 14)Despite the beneficial effects of androgens in therapies for osteoporosis, hypogonadism and other androgen deficient diseases, clinical use of them has been limited because of the undesirable virilizing (acne, hirsu...
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