This paper examines the central role of social and political institutions behind motivations and strategies of ethnic Chinese Singaporean investment in Hainan, China. Drawing upon 22 case studies of Singaporean firms in Hainan, we show that Singaporean investment in Hainan is embedded in Chinese business networks and their associated institutions. At the personal level, direct investments are largely motivated by the cultural attachments of Singaporean Hainanese to Hainan. Their small‐ and medium‐sized joint ventures largely reflect the characteristics of ethnically‐based Chinese business networks that stress connections, or guanxi. Similarly, the influence of social organizations (e.g., clan associations) and government institutions (e.g., public and quasi‐public agencies) on Singaporean investment strategies in Hainan reveals the significance of ongoing social relations institutionalized at the broader societal level. 相似文献
Better quantification of continental water storage variations is expected to improve our understanding of water flows, including evapotranspiration, runoff and river discharge as well as human water abstractions. For the first time, total water storage (TWS) on the land area of the globe as computed by the global water model WaterGAP (Water Global Assessment and Prognosis) was compared to both gravity recovery and climate experiment (GRACE) and global positioning system (GPS) observations. The GRACE satellites sense the effect of TWS on the dynamic gravity field of the Earth. GPS reference points are displaced due to crustal deformation caused by time-varying TWS. Unfortunately, the worldwide coverage of the GPS tracking network is irregular, while GRACE provides global coverage albeit with low spatial resolution. Detrended TWS time series were analyzed by determining scaling factors for mean annual amplitude (fGRACE) and time series of monthly TWS (fGPS). Both GRACE and GPS indicate that WaterGAP underestimates seasonal variations of TWS on most of the land area of the globe. In addition, seasonal maximum TWS occurs 1 month earlier according to WaterGAP than according to GRACE on most land areas. While WaterGAP TWS is sensitive to the applied climate input data, none of the two data sets result in a clearly better fit to the observations. Due to the low number of GPS sites, GPS observations are less useful for validating global hydrological models than GRACE observations, but they serve to support the validity of GRACE TWS as observational target for hydrological modeling. For unknown reasons, WaterGAP appears to fit better to GPS than to GRACE. Both GPS and GRACE data, however, are rather uncertain due to a number of reasons, in particular in dry regions. It is not possible to benefit from either GPS or GRACE observations to monitor and quantify human water abstractions if only detrended (seasonal) TWS variations are considered. Regarding GRACE, this is mainly caused by the attenuation of the TWS differences between water abstraction variants due to the filtering required for GRACE TWS. Regarding GPS, station density is too low. Only if water abstractions lead to long-term changes in TWS by depletion or restoration of water storage in groundwater or large surface water bodies, GRACE may be used to support the quantification of human water abstractions. 相似文献
The study of nonequilibrium, self-gravitating, compressible, homogeneous and uniformly rotating gaseous ellipsoidal models
is extended from parallel to nonparallel angular velocity and vorticity. The differential equations of motion governing these
models are numerically integrated over ranges of initial values of angular velocity and vorticity.
The dynamical behaviour of the ellipsoid is found to be almost unchanged when the initial values of Ω3/Ω3,e and λ3/λ3,e are interchanged, where λ is a function of the vorticity, Ω3 is the angular velocity along the x3 axis, and Ω3,e and λ3,e are equilibrium values.
Models with the same initial value of | Ω3/Ω3,e - λ3/λ3,e | have similar dynamical behaviour. When this value becomes larger, the oscillations of the semi-axes are larger and are
more nonperiodic.
For all models, the ellipsoidal configuration is maintained at all times.
The magnitude of Ωl depends on the difference between the values of the semi-axes am and an, where l, m, and n are cyclic. The smaller this difference is, the larger the angular velocity along the third axis. Thus
whenever the model approaches a spheroidal configuration, there may be a large and rapid increase in the angular velocity
along the axis of ‘symmetry’.
The last two properties, namely the maintenance of the ellipsoidal configuration and the large increase in angular velocity
of the model, configuration also hold in the model (T.T.Chia and S.Y.Pung, 1995, Astrophys.\ Space Sci., 229, 215.) with parallel
angular velocity and vorticity.
However, unlike the earlier model, Ω2 and Ω3 are observed to reverse their directions at certain instants during the oscillations; this may have interesting astrophysical
implications.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
Most fishes suffer high mortality during early development stages. The existence of a “critical period” was hypothesized by
Hjort (1914). However, several decades of research have resulted in considerable controversy over the hypothesis. This paper
attempts to clarify the critical period concept, demonstrate its usefulness, and resolve some of the controversy surrounding
it.
Based on our own studies and the literature, we find that within the “aquaculture school” (those concerned with culturing
fishes, particulary larval stages), there is a great deal of evidence for the critical period concept. But we redefine the
concept of “critical period” of mortality of fish larvae in this way. The deepest, sharpest, and fastest physiological and
ecological changes during the development of the larvae are produced with the shift from endogenous nutrition to exogenous.
At this stage, the old functions are quickly being replaced by new functions inside the body. Because of this shifting of
function and imperfection of organs, the larvae are most sensitive at this time to environmental factors, particularly food
supply. A higher specific mortality rate often occurs immediately folowing the period of strictly endogenous yolk feeding,
and during the period of first exogenous feeding. Then it may be followed by a lower specific mortality rate.
The significance of a “critical period” for fish populations is discussed. A good understanding of the “critical period” would
provide a means for predicting the strength of year classes in natural fish populations, and also suggests approaches for
increasing survival in aquaculture systems. 相似文献
We analyze the interannual monthly variability of oxygen isotope ratios in data from IAEA stations along the Atlantic coast of South America between 23° and 34° S to evaluate the influence of parameters such as temperature, rainfall amount and moisture source contribution on meteoric water recharging two karst systems in subtropical Brazil. In addition, a 2 year monitoring program performed on soil and cave drip and rimstone pool waters from sampling sites with contrasting discharge values and located at 100 and 300 m below the surface in the Santana Cave System (24°31′ S; 48°43′ W), is used to test the influence of hydrologic and geologic features on the temporal variations of seepage water δ18O.
Interannual monthly variations in δ18O of rainfall reflect primarily regional changes in moisture source contribution related to seasonal shifts in atmospheric circulation from a more monsoonal regime in summer (negative values of δ18O) to a more extratropical regime in winter (positive values of δ18O). Variations in groundwater δ18O indicate that the climatic signal of recent rainfall events is rapidly transmitted through the relatively deep karst aquifer to the cave drip waters, regardless of location of collection in the cave. In addition, the data also suggest that water replenishment in the system is triggered by the increase in hydraulic head during periods when recharge exceeds the storage capacity of the soil and epikarst reservoirs. Significant perturbations in the groundwater composition, characterized by more positive values of δ18O, are probably connected to an increased Atlantic moisture contribution associated with extratropical precipitation. This implies that the δ18O of speleothems from caves in this region may be a suitable proxy for studying tropical–extratropical interactions over South America, a feature that is intrinsically related to the global atmospheric circulation. 相似文献
The significance of flow in the matrix of the Chalk unsaturated zone, in comparison with flow in fractures, has been the subject of much debate. In this article, important elements of the literature are discussed in detail and several simple modelling analyses based on steady-state flow are presented. A study of the sensitivity of solute spreading to fracture spacing in models that ignore matrix flow shows that this latter assumption is generally incompatible with observed solute profiles, unless unrealistically small fracture spacings are assumed. The effect of air phase continuities (e.g. bedding planes) on matrix flow has also been examined. These discontinuities are frequently interrupted by points of connectivity between matrix blocks. An issue therefore is the relationship between connectivity and its effect on inter-block conductance. A simple analysis of the Laplace equation shows that just 1% connectivity represents an effective pathway equivalent to 18% of the local rock hydraulic conductivity. Obviously, when there is no fracture flow, solute spreading is significantly reduced. However, dual permeability model simulations show that matrix flow reduces solute spreading in the presence of persistent fracture flow. All of the above studies suggest that flow in the matrix of the Chalk unsaturated zone is significant and that ignoring it may result in a serious misunderstanding of the system. 相似文献
The kimberlite pipe at Rietfontein has been found to contain a suite of ultrabasic xenoliths, amongst which are kyanite eclogites of unusual freshness. The kyanite crystals are of varying shades of blue. Physical properties of some of the primary minerals together with the chemical composition of four kyanite eclogites and of a light and a dark blue kyanite crystal are presented.The xenoliths found in the Rietfontein Pipe are compared with those found in the Zagadochnaya Pipe and certain similarities and differences noted. 相似文献