从“从游”到“同游”:面向未来的理想型师生关系构建

师生关系一直是教育实践的难点及教育研究的热点。在高深学问的掌握及研究水平方面存在的差异,决定了高校师生关系“从游”的现实性,但是容易异化成权威性师生关系。对于高深知识的学术探索,决定研究生与导师的师生关系应追求超越性的“同游”式师生关系。从“从游”式师生关系到“同游”式师生关系的构建路径,包括提升研究生的研究能力、明确导师的指导责任、保持具有教育智慧的开放心态。

Zoospore-derived monoecious gametophytes in Undaria pinnatifida(Phaeophyceae)

The annual life cycle of the brown seaweed Undariapinnatifida （Harvey） Suringer comprises a macroscopic diploid sporophyte stage and a microscopic haploid gametophyte stage. In 2011, an unusual zoospore-derived monoecious gametophyte isolate （designated as line 10-5-3） of U. pinnatifida was observed. To understand this phenomenon, a comprehensive screening of eighty-two previously identified male gametophyte cultures, isolated from three randomly selected cultivars （lines 10, 7, and 5） was performed. Thirty-six of the isolates developed both antheridia and oogonia on the same filamentous fragment in a standard gametogenesis test （SGT： 18℃, 60 umol photons/（m2.s））. Selfing of the monoecious gametophyte or crossing it with a normal male gametophyte both gave rise to morphologically normal sporophytic offspring. However, crossing resulted in a much higher fertilization rate （89.7%）. The hybrid and selfed sporophytic offspring were grown to maturity in flow tanks at an ambient temperature of 10-18℃ over a period of 69 days. Active zoospores were released from both types of mature sporophylls. The majority of these developed into male gametophytes, while 15%-20% developed into the observed monoecious structures on the same filament. Using PCR amplification it was found that all the monoecious gametophyte isolates and the sporophytic offspring resulting from the selfing and crossing lacked the femalelinked microsatellite sequence （a part of the locus Up-AC-2A8, GenBank accession No. AY738602.1）, indicating their male nature. U.pinnatifida is an invasive species in some regions and the implications of the above findings for this species in nature are briefly discussed.

Sea surface temperature and salinity reconstruction based on stable isotopes and Mg/Ca of planktonic foraminifera in the western Pacific Warm Pool during the last 155 ka

Changes in sea surface temperature （SST）, seawater oxygen isotope （δ18Osw）, and local salinity proxy （δ18Osw-ss ） in the past 155 ka were studied using a sediment core （MD06-3052） from the northern edge of the western Pacific Warm Pool （WPWP）, within the flow path of the bifurcation of the North Equatorial Current. Our records reveal a lead-lag relationship between paired Mg/Ca-SST and δ18O during Termination II and the last interglacial period. Similarity in SST between our site and the Antarctic temperature proxy and in CO2 profile showed a close connection between the WPWP and the Antarctic. Values of 818Osw exhibited very similar variations to those of mean ocean δ18Osw, owing to the past sea-level changes on glacial-interglacial timescale. Calculated values of δ18O reflect a more saline condition during high local summer insolation （SI） periods. Such correspondence between δ18O and local SI in the WPWP may reflect complex interaction between ENSO and monsoon, which was stimulated by changes in solar irradiance and their influence on the local hydrologic cycle. This then caused a striking reorganization of atmospheric circulation over the WPWP.

Diagnosis of Physical and Biological Control over Phytoplankton in the Gulf of Maine-Georges Bank Region Using an Adjoint Data Assimilation Approach

The linkage between physical and biological processes, particularly the effect of the circulation field on the distribution of phytoplankton, is studied by applying a two-dimensional model and an adjoint data assimilation approach to the Gulf of Maine-Georges Bank region. The model results, comparing well with observation data, reveal seasonal and geographic variations of phytoplankton concentration and verify that the seasonal cycles of phytoplankton are controlled by both biological sources and advection processes which are functions of space and time and counterbalance each other. Although advective flux divergences have greater magnitudes on Georges Bank than in the coastal region of the western Gulf of Maine, advection control over phytoplankton concentration is more significant in the coastal region of the western Gulf of Maine. The model results also suggest that the two separated populations in the coastal regions of the western Gulf of Maine and on Georges Bank are self-sustaining.

Characteristics of the δ15NNO3 distribution and its drivers in the Changjiang River estuary and adjacent waters

In this study, we conducted investigations in the Changjiang （Yangtze） River estuary and adjacent waters （CREAW） in June and November of 2014. We collected water samples from different depths to analyze the nitrogen isotopic compositions of nitrate, nutrient concentrations （including inorganic N, P, and Si）, and other physical and biological parameters, along with the vertical distribution and seasonal variations of these parameters. The compositions of nitrogen isotope in nitrate were measured with the denitrifier method. Results show that the Changjiang River diluted water （CDW） was the main factor affecting the shallow waters （above 10 m） of the CREAW, and CDW tended to influence the northern areas in June and the southern areas in November. 615Nrqo~ values in CDW ranged from 3.21%o-3.55%o. In contrast, the deep waters （below 30 m） were affected by the subsurface water of the Kuroshio Current, which intruded into the waters near 3 I^N in June. The ~iI^NNo3 values of these waters were 6.03%0-7.6%0, slightly higher than the values of the Kuroshio Current. Nitrate assimilation by phytoplankton in the shallow waters of the study area varied seasonally. Because of the favorable temperature and nutrient conditions in June, abundant phytoplankton growth resulted in harmful algae blooms （HABs）. Therefore, nitrate assimilation was strong in June and weak in November. The ~15NNo3 fractionations caused by assimilation of phytoplankton were 4.57%0 and 4.41%o in the shallow waters in June and November, respectively. These results are consistent with previous laboratory cultures and in situ investigations. Nitrification processes were observed in some deep waters of the study area, and they were more apparent in November than in June. The fractionation values of nitrification ranged from 24%0-25%o, which agrees with results for Nitrosospira tenuis reported by previous studies.

From Home Food to Macanese Cuisine？ Historical Development, Tourist Branding and Cultural Identity

Food, cooking, and food-making places play a primordial role in the formation of cultural identity and community building. Using the example of Macanese food in Macao Special Administrative Region, this article discusses the transformation of Macanese food from everyday home food to the current status of cuisine in present-day Macanese society through the analysis of the perception of consumers and producers of Macanese food. The findings demonstrate the friction between Macanese food crafted by Macanese as part of an emergent ＂authentic＂ marker of Macanese identity and the commercial branding of Macanese food for tourist purposes.

Carbon and nitrogen isotopes analysis and sources of organic matter in the upper reaches of the Chaobai River near Beijing,China

The carbon and nitrogen isotopes in the surface sediments,plants,and soil in the upper reaches of the Chaobai River have been researched.The results showed 27.75‰-21.58‰ and 1.32‰-6.74‰ for carbon and nitrogen isotopic ratios in the surface sediments,respectively.The sources of sedimentary organic matter in this area are soil organic matter,aquatic vascular plants,and riverine plankton,respectively,and a significant contributor to sediment in the Chaohe River,the Baihe River,and the Miyun Reservoir areas is soil organic matter.Furthermore,part of sedimentary organic matter in the Miyun Reservoir is attributed to the input from the Chaohe River and the Baihe River,the other is from C4 vegetation growing around individual point stations at the Miyun Reservoir.Compared with the situation in Hebei Province,the contribution of soil organic matter decreased significantly and river plankton and aquatic vascular plants increased significantly in Beijing municipal areas.This study reveals that the source of organic matter has a close relationship with the soil erosion.

A new paleoenvironmental index for anoxic events—Mo isotopes in black shales from Upper Yangtze marine sediments

This paper investigates the high-solution of Mo isotopes and uses trace-element analyses for fresh and representative black shales and siliceous shales collected from the transition between the Late Ordovician and the Early Silurian at the Wangjiawan section in Yichang and the Late Permian Dalong Formation in the Shangsi Section of Sichuan. The applicability of different geochemical parameters used as paleo-oxygenation indices are also compared. The preliminary results show that V/（V＋Ni）, Uauth （auth U）, V/Cr, Ceanom and U/Th have a scattered variation range, but most samples plot within the suboxic-anoxic fields. The suboxic-anoxic environment was dominant during the deposition and formation of the two anoxic facies. These redox indicators show little correspondence to the δ98M0 values. The U/Mo ratio can be used as a potential proxy for the paleo-redox conditions due to the possibility that Mo is enriched relative to U at different redox gradients during early diagenesis. This evidence is more significant for the euxinicity condition and corresponds to positive δ98M0 （〉1.5%o） values with low U/Mo ratios. This evidence is likely related to the depositional conditions near the boundary between anoxic and euxinic environ- ments, which are characterised by low bioturbation or water circulation. Other samples reveal a wide scatter of U/Mo ratios and δ98M0 〈1.5%0. These results are likely due to punctuated improvements in oxygenation with intense bioturbation or water circulation, which led to the redistribution of trace element.

A Widening Tourism Deficit

During the week-long National Day holiday(October 1-7),nearly 480 million tourist trips were made by Chinese people,a yearon-year increase of more than 10 percent,according to the latest survey from the China Tourist Academy.The figure 480 million represents a larger number than the populations of Germany,France,U.K.,Italy,Spain and Japan combined.

Anterolateral thigh free flap for simultaneous reconstruction of digital extensor tendon and defect of the dorsal hand： A case report

This paper describes a new technique in the repair of the hand defect with digital extensor tendon injury. The anterolateral thigh flap with the thick femoral fascia has been used in the reconstruction of the composite defect of the dorsal hand, especially the defect of tendon. This technique requires short period of treatment and hence causes less damage to the donor site but shows a better recovery of the hand function. A favorable curative effect has been obtained in this patient.

Estimates for the Tail Probability of the Supremum of a Random Walk with Independent Increments

The authors investigate the tail probability of the supremum of a random walk with independent increments and obtain some equivalent assertions in the case that the increments are independent and identically distributed random variables with Osubexponential integrated distributions.A uniform upper bound is derived for the distribution of the supremum of a random walk with independent but non-identically distributed increments,whose tail distributions are dominated by a common tail distribution with an O-subexponential integrated distribution.