The surface uplift history of the Tibetan Plateau and Himalaya is among the most interesting topics in geosciences because of its effect on regional and global climate during Cenozoic time, its influence on monsoon intensity, and its reflection of the dynamics of continental plateaus. Models of plateau growth vary in time, from pre-India-Asia collision (e.g., Ϸ100 Ma ago) to gradual uplift after the India-Asia collision (e.g., Ϸ55 Ma ago) and to more recent abrupt uplift (<7 Ma ago), and vary in space, from northward stepwise growth of topography to simultaneous surface uplift across the plateau. Here, we improve that understanding by presenting geologic and geophysical data from north-central Tibet, including magnetostratigraphy, sedimentology, paleocurrent measurements, and 40 Ar/ 39 Ar and fission-track studies, to show that the central plateau was elevated by 40 Ma ago. Regions south and north of the central plateau gained elevation significantly later. During Eocene time, the northern boundary of the protoplateau was in the region of the Tanggula Shan. Elevation gain started in pre-Eocene time in the Lhasa and Qiangtang terranes and expanded throughout the Neogene toward its present southern and northern margins in the Himalaya and Qilian Shan.climate ͉ tectonics ͉ magnetostratigraphy ͉ Hoh Xil Basin ͉ Cenozoic T he Tibetan Plateau is the most extensive region of elevated topography in the world (Fig. 1). How such high topography, which should have an effect on climate, monsoon intensity, and ocean chemistry (1-5), has developed through geologic time remains disputed. Various lines of investigation, including evidence from the initiation of rift basins (6), potassium-rich (K-rich) volcanism (7), tectonogeomorphic studies of fluvial systems and drainage basins (8), thermochronologic studies (9), upper-crustal deformation histories (10, 11), stratigraphic and magnetostratigraphic studies of sediment accumulation rates (12), paleobotany (13), and oxygen isotope-based paleoaltimetry (14-22), have suggested different uplift histories. Authors of recent geologic studies (11) have proposed that significant crustal thickening (and by inference, surface uplift) in the Qiangtang terrane occurred in the Early Cretaceous [Ϸ145 mega-annum (Ma) age], followed by major crustal thickening within the Lhasa terrane between Ϸ100 and 50 Ma ago. This hypothesis remains disputed (23). Other models of plateau growth range from Oligocene (e.g., Ϸ30 Ma ago) gradual surface uplift (7) to more recent (Ͻ7 Ma ago) and abrupt surface uplift (24), with oblique stepwise growth of elevation northward and eastward after the India-Eurasia collision (7,20,25,26). With few exceptions (e.g., see refs. 11 and 27), most of these models focus on data from the Himalaya and southern Tibet and remain relatively unconstrained by geologic data from the interior of the Tibetan Plateau.The Hoh Xil Basin (HXB) of the north-central Tibetan Plateau (Figs. 1 and 2) is the most widespread exposure of Paleogene sediments on the high plateau and contains Ͼ5,000...

Combined analyses of deep tow magnetic anomalies and International Ocean Discovery Program Expedition 349 cores show that initial seafloor spreading started around 33 Ma in the northeastern South China Sea (SCS), but varied slightly by 1-2 Myr along the northern continent-ocean boundary (COB). A southward ridge jump of 20 km occurred around 23.6 Ma in the East Subbasin; this timing also slightly varied along the ridge and was coeval to the onset of seafloor spreading in the Southwest Subbasin, which propagated for about 400 km southwestward from 23.6 to 21.5 Ma. The terminal age of seafloor spreading is 15 Ma in the East Subbasin and 16 Ma in the Southwest Subbasin. The full spreading rate in the East Subbasin varied largely from 20 to 80 km/Myr, but mostly decreased with time except for the period between 26.0 Ma and the ridge jump (23.6 Ma), within which the rate was the fastest at 70 km/ Myr on average. The spreading rates are not correlated, in most cases, to magnetic anomaly amplitudes that reflect basement magnetization contrasts. Shipboard magnetic measurements reveal at least one magnetic reversal in the top 100 m of basaltic layers, in addition to large vertical intensity variations. These complexities are caused by late-stage lava flows that are magnetized in a different polarity from the primary basaltic layer emplaced during the main phase of crustal accretion. Deep tow magnetic modeling also reveals this smearing in basement magnetizations by incorporating a contamination coefficient of 0.5, which partly alleviates the problem of assuming a magnetic blocking model of constant thickness and

No abstract

[1] Results of clay mineralogy, major element geochemistry, and Sr and Nd isotopes in 93 argillaceous samples collected from drainage basins of the Pearl, Red, and Mekong rivers reveal different degrees of chemical weathering in Southeast Asia despite similar climate conditions across these regions. The kaolinite/illite ratio, illite chemistry index, and illite crystallinity can be used as indicators of chemical weathering intensity. These mineralogical proxies combined with the K 2 O/(Na 2 O + CaO) molar ratio, chemical index of alteration (CIA), and weathering trends observed from major element results indicate intensive silicate weathering in the Pearl River basin, moderate to intensive in the Mekong River basin, and moderate in the Red River basin. Although a significant modification of eNd (0) Sr ratios are controlled by various states of chemical weathering of high-Sr minerals such as plagioclase (rich in Na and Ca) with a linear decrease trend from the Pearl, Mekong, to Red river basins. Our results suggest that it is not the warm climate with heavy monsoon precipitation but tectonics playing the most significant role in controlling weathering and erosion processes in south China and Indochina Peninsula. Strong physical erosion caused by tectonic activities and river incision along the eastern margin of the Tibetan Plateau and along the Red River fault system is responsible for high contents of primary minerals in the lowlands of Red and Mekong river basins.

BackgroundIn recent years in China, the tense physician-patient relationship has been an outstanding problem. Empathy is one of the fundamental factors enhancing the therapeutic effects of physician-patient relationships and is significantly associated with clinical and academic performance among students.MethodsThis cross-sectional study used the JSPE-S (The Student Version of the Jefferson Scale of Physician Empathy) to assess 902 medical students from 1st year to 4th year at China Medical University. The reliability of the questionnaire was assessed by Cronbach’s alpha coefficient. We performed an exploratory factor analysis to evaluate the construct validity of the JSPE-S. Group comparisons of empathy scores were conducted via the t-test and one-way ANOVA. Statistic analysis was performed by SPSS 13.0.ResultsThe Cronbach’s alpha coefficient was 0.83. The three factors emerging in the factor analysis of the JSPE-S are “perspective taking”, “compassionate care” and “ability to stand in patients’ shoes”, which accounted for 48.00%. The mean empathy score was 109.60. The empathy score of medical students had significant differences between different genders (p < 0.05) and academic year level (p < 0.05).ConclusionsThis study provided support for the validity and reliability of the Chinese translated version of the JSPE-S for medical students. Early exposure to clinical training and a curriculum for professional competencies help to enhance the empathy of medical students. We suggest that the curriculum within Chinese medical schools include more teaching on empathy and communicational skills.