A tale of two population crises in recent Chinese history

The fall of the Ming dynasty in the first half of the 17th century and the Taiping Rebellion from 1851-1864 were two of the most chaotic periods in Chinese history, and each was accompanied by large-scale population collapses. The 'Kang-Qian Golden Age' (also known as 'High Qing'), during which population size expanded rapidly, falls in between the two. Scholars remain divided in their opinions concerning the above alternation of population growth and decline as to whether variations in population size or climate change should be identified as the root cause. In either case, the synergistic impact of population growth and climate change upon population growth dynamics is overlooked. In the present study, we utilized high-resolution empirical data, qualitative survey, statistical comparison and time-series analysis to investigate how the two factors worked synergistically to drive population cycles in 1600-1899. To facilitate our research, we posited a set of simplified pathways for population growth in historical agrarian China. Our results confirm that the interrelation between population growth, climate change and population crises in recent Chinese history basically followed our posited pathways. The recurrences of population crises were largely determined by the combination of population growth and climate change. Our results challenge classic Malthusian/post-Malthusian interpretations and historians' views of historical Chinese population cycles. © 2012 The Author(s).published_or_final_versionSpringer Open Choice, 28 May 201

First experience of non-fluoroscopic magnetic electroanatomic mapping guided alcohol ablation of the atrioventricular node

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Non-fluoroscopic magnetic electroanatomic mapping of pulmonary veins during spontaneous or induced prematuer depolarization to guide radiofrequency ablation of focal atrial fibrillation

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Sudden cardiac death: Prevention and treatment

Sudden cardiac death remains a major health issue in western countries as well as in Hong Kong. Despite increasing knowledge of the mechanisms and risk factors of sudden cardiac death, methods for identifying high-risk candidates and predicting the efficacy of measures to prevent sudden cardiac death are still inadequate. A significant proportion of patients have known heart disease but are generally considered to be at low risk for this event. More efforts are needed to improve the success rate of out-of-hospital resuscitation through better warning systems, the use of amiodarone for refractory arrhythmias, and the widespread availability of automated defibrillation devices to allow early defibrillation. It is likely that these measures could increase the number of survivors following cardiac arrest. In survivors of sudden cardiac death episodes, treatment of the underlying cardiac disease, especially early revascularisation for myocardial ischaemia, is required. In the majority of patients, implantation of an implantable cardioverter defibrillator, with or without the use of an anti-arrhythmic drug such as amiodarone, would then be used to maintain survival. Furthermore, for individuals at significant risk of sudden cardiac death, primary prevention of sudden cardiac death through the placement of an implantable cardioverter defibrillator is increasingly being used.published_or_final_versio

Regional Geographic Factors Mediate the Climate-war Relationship in Europe

It has been demonstrated in recent studies by that wars occurred with greater frequency in Europe in periods of cold climate over the past millennium, and food scarcity is the explanation. However, the issue of whether the climate-war relationship holds consistently across the European continent has been insufficiently explored. In the present study, we seek to advance the macroscopic understanding of the climate-war association in Europe via the statistical analysis of fine-grained paleo-climate and historical warfare data covering the period 1400–1999, with a specific focus on how regional geographic factors mediate the association. Our statistical results show that the climate-war correlation varied across Europe. At multi-centennial time-scale, temperature-war correlation was stronger in Eastern Europe, in part because of the region’s greater dependence on agriculture and in part due to the region’s prevailing continental climate. At multi-decadal to centennial time-scale, the temperature-war correlation in Europe was periodically distorted when population pressure was unleashed via a significant decline in the rate of population growth or through industrialization. Furthermore, the regional disparity in terms of population growth rate and pace of industrialization might be responsible for the diverse trends and trajectories of the temperature-war correlation in Eastern Europe and Western Europe. Our results may help to resolve some major controversies about the climate-conflict link.published_or_final_versio

Quantifying the intra-regional precipitation variability in northwestern China over the past 1,400 years

There has been a surge of paleo-climatic/environmental studies of Northwestern China (NW China), a region characterized by a diverse assortment of hydro-climatic systems. Their common approach, however, focuses on "deducing regional resemblance" rather than "exploring regional variance." To date, efforts to produce a quantitative assessment of long-term intra-regional precipitation variability (IRPV) in NW China has been inadequate. In the present study, we base on historical flood/drought records to compile a decadal IRPV index for NW China spanned AD580-1979 and to find its major determinants via wavelet analysis. Results show that our IRPV index captures the footprints of internal hydro-climatic disparity in NW China. In addition, we find distinct similar to 120-200 year periodicities in the IRPV index over the Little Ice Age, which are attributable to the change of hydro-climatic influence of ocean-atmospheric modes during the period. Also, we offer statistical evidence of El Nino Southern Oscillation (Indo-Pacific warm pool sea surface temperature and China-wide land surface temperature) as the prominent multi-decadal to centennial (centennial to multi-centennial) determinant of the IRPV in NW China. The present study contributes to the quantitative validation of the long-term IRPV in NW China and its driving forces, covering the periods with and without instrumental records. It may help to comprehend the complex hydro-climatic regimes in the region.published_or_final_versio

Human induced pluripotent stem cell-derived mesenchymal stem cells are superior to adult bone marrow-derived mesenchymal stem cells in the treatment of limb ischemia

Conference invited speaker: Dr. Lian, QOral Presentation: Session S31 - Genetic Determinants of Heart Disease, Gene and Cell Based Therapies, Basic Research: abstract no. 1489postprintThe 16th World Congress on Heart Disease of the International Academy of Cardiology Annual Scientific Sessions 2011, Vancouver, B.C., 23-27 July 2011

Atrial fibrillation: Prevention and termination with pacing

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Is radiofrequency catheter ablation of symptomatic ventricular ectopics justified?

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Cyclic ADP ribose is a novel regulator of intracellular Ca 2+ oscillations in human bone marrow mesenchymal stem cells

Bone marrow mesenchymal stem cells (MSCs) are a promising cell source for regenerative medicine. However, the cellular biology of these cells is not fully understood. The present study characterizes the cyclic ADP-ribose (cADPR)-mediated Ca 2+ signals in human MSCs and finds that externally applied cADPR can increase the frequency of spontaneous intracellular Ca 2+ (Ca 2+ i) oscillations. The increase was abrogated by a specific cADPR antagonist or an inositol trisphosphate receptor (IP3R) inhibitor, but not by ryanodine. In addition, the cADPR-induced increase of Ca 2+ i oscillation frequency was prevented by inhibitors of nucleoside transporter or by inhibitors of the transient receptor potential cation melastatin-2 (TRPM2) channel. RT-PCR revealed mRNAs for the nucleoside transporters, concentrative nucleoside transporters 1/2 and equilibrative nucleoside transporters 1/3, IP3R1/2/3 and the TRPM2 channel, but not those for ryanodine receptors and CD38 in human MSCs. Knockdown of the TRPM2 channel by specific short interference RNA abolished the effect of cADPR on the Ca 2+ i oscillation frequency, and prevented the stimulation of proliferation by cADPR. Moreover, cADPR remarkably increased phosphorylated extracellular-signal-regulated kinases 1/2 (ERK1/2), but not Akt or p38 mitogen-activated protein kinase (MAPK). However, cADPR had no effect on adipogenesis or osteogenesis in human MSCs. Our results indicate that cADPR is a novel regulator of Ca 2+ i oscillations in human MSCs. It permeates the cell membrane through the nucleoside transporters and increases Ca 2+ oscillationviaactivation of the TRPM2 channel, resulting in enhanced phosphorylation of ERK1/2 and, thereby, stimulation of human MSC proliferation. This study delineates an alternate signalling pathway of cADPR that is distinct from its well-established role of serving as a Ca 2+ messenger for mobilizing the internal Ca 2+ stores. Whether cADPR can be used clinically for stimulating marrow function in patients with marrow disorders remains to be further studied. © 2011 The Authors © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.postprin