Mass Human Migration and the Urban Heat Island during the Chinese New Year Holiday: A Case Study in Harbin City, Northeast China

Many Chinese people leave big cities for family reunions during the Chinese New Year （CNY）, which is the most important public holiday in China. However, how modem mass human migration during the CNY holiday affects the urban heat island （UHI） is still un- known. Here, the authors investigate the role of modem human migration for the UHI effects during the CNY holiday for the period of 1992-2006 in Harbin City, Northeast China. The results show that during the CNY week, the UHI effects expressed as daily mean, maxi- mum, and minimum temperature differences between urban and rural stations averaged over the period of 1992-2006 are 0.65℃ （43%）, 0.31℃ （48%）, and 1.14℃ （71%） lower than during the background period （four weeks before and four weeks after the CNY week）, re- spectively. Our findings identify previously unknown impacts of modem mass human migration on the UHI effects based on a case study in Harbin City.

Upregulation of macrophage migration inhibitory factor and calgizzarin by androgen in TM4 mouse Sertoli cells

Aim： To identify proteins induced by androgen in Sertoli cells during spermatogenesis. Methods： We analyzed protein profiles in TM4 Sertoli cells treated with dihydrotestosterone （DHT） using surface enhanced laser desorption ionization time-of-flight mass spectrometry （SELDI-TOF-MS）. Results： We found increases in the expression of a 5.0-kDa protein at 15 min, an 11.3-kDa protein at 24 h and 4.3 kDa, 5.7 kDa, 5.8 kDa, 9.95 kDa and 9.98 kDa proteins at 48 h after the treatment. In contrast, the expression of 6.3 kDa and 8.6 kDa proteins decreased at 30 min, and 4.9 kDa, 5.0 kDa, 12.4 kDa and 19.8 kDa proteins at 48 h after the treatment. The ll.3-kDa protein was identified as macrophage migration inhibitory factor （MIF） known to having various functions. The 9.98-kDa protein was identified as calgizzarin related to calcium channels. The timing of their expression suggests that MIF and calgizzarin are involved in late regulation of spermatogenesis in Sertoli cells by androgen. Conclusion： MIF and calgizzarin are two important androgen-responsive proteins produced by Sertoli cells and they might play a role in regulating spermatogenesis.

Mass human migration and Beijing's urban heat island during the Chinese New Year holiday

Population movements around the Chinese New Year （CNY）, which are much larger in recent years than before, are the largest annual human migration in the world. However, it is still largely unknown how or to what extent such mass human migration affects urban climate. Here, we investigate the role of mass human migration in influencing Beijing＇s urban heat island （UHI） during the CNY holiday for the period of 2004-2013. We find that the UHI effects expressed as daily mean （ATmean）, maximum （ATmax）, and minimum （ATmin） temperature differences between urban and rural areas show a weakening trend during the CNY week relative to the background period （4 weeks including 2-3 weeks before and 2-3 weeks after the CNY week）. In particular, large reductions occurred during the CNY week for the period of 2009-2013, when nearly half of population left the city before the CNY holiday. △Tmean, △Tmax, and △Tmin averaged over the period of 2009-2013 during the CNY week were 0.64, 0.45, and 0.83 ℃ lower than during the background period, representing relative reductions of 35 %, 66 %, and 27 %, respectively. Our findings highlight the important role of modem mass human migration for urban climate based on a case study in Beijing.