Linking Perceived Risk of Public Health Emergency to Psychological Distress among Chinese College Students: The Chain Mediation Role of Balanced Time Perspective and Negative Coping Styles

Background:With public health emergencies(PHE)worldwide increasing,the perceived risk of PHE has been one of the critical factors influencing college students’psychological distress.However,the mechanisms by which the perceived risk of PHE affects college students’psychological distress are not clear.The study’s purpose was to investigate the mediation roles of deviation from a balanced time perspective(DBTP)and negative coping styles between the perceived risk of PHE and psychological distress.Methods:A convenience sampling method was used to survey 1054 Chinese college students with self-reporting.Data was collected using the Public Risk Perception Scale(PRPS),the Zimbardo Time Perspective Inventory(ZTPI),the Simplified Coping Style Questionnaire(SCSQ),the PHE Anxiety Scale,and the Chinese version of the Patient Health Questionnaire(PHQ).The associations between the perceived risk of PHE,DBTP,negative coping styles,and psychological distress were clarified using the correlation analysis.Additionally,the mediating roles of DBTP and negative coping styles between the perceived risk of PHE and psychological distress were investigated using a structural equation model.Results:The findings revealed low to moderate correlations between the variables studied.Students’perceived risk of PHE was a positive predictor of their psychological distress(b=0.219,p<0.01).DBTP and negative coping styles played chain mediation roles between them with the effect being 0.009 and a 95%Boot CI of[0.003,0.023].This chain mediation model had an excellent fit index(χ^(2)/df=4.732,CFI=0.973,TLI=0.930,RMSEA=0.048,SRMR=0.047).Conclusion:These findings showed how the perceived risk of PHE affected college students’psychological distress.Specifically,these results suggested that improving students’mental ability to switch effectively among different time perspectives depending on task features and situational considerations and reducing their negative coping styles might be effective ways to promote their mental health.

Impacts of Increasing Model Resolutions and Shortening Forecast Lead Times on QPFs in South China During the Rainy Season

This study investigated the impacts of increasing model resolutions and shortening forecast lead times on the quantitative precipitation forecast(QPF)for heavy-rainfall events over south China during the rainy seasons in 2013-2020.The control experiment,where the analysis-forecast cycles run with model resolutions of about 3 km,was compared to a lower-resolution experiment with model resolutions of about 9 km,and a longer-term experiment activated 12 hours earlier.Rainfall forecasting in the presummer rainy season was significantly improved by improving model resolutions,with more improvements in cases with stronger synoptic-scale forcings.This is partially attributed to the improved initial conditions(ICs)and subsequent forecasts for low-level jets(LLJs).Forecasts of heavy rainfall induced by landfalling tropical cyclones(TCs)benefited from increasing model resolutions in the first 6 hours.Forecast improvements in rainfall due to shortening forecast lead times were more significant at earlier(1-6 h)and later(7-12 h)lead times for cases with stronger and weaker synoptic-scale forcings,respectively,due to the area-and case-dependent improvements in ICs for nonprecipitation variables.Specifically,significant improvements mainly presented over the northern South China Sea for low-level onshore wind of weak-forcing cases but over south China for LLJs of strong-forcing cases during the presummer rainy season,and over south China for all the nonprecipitation variables above the surface during the TC season.However,some disadvantages of higher-resolution and shorter-term forecasts in QPFs highlight the importance of developing ensemble forecasting with proper IC perturbations,which include the complementary advantages of lower-resolution and longer-term forecasts.

The role of time preferences in contract breach:Evidence from Chinese poultry farmers participating in contract farming

Farmers’contract breach behavior is cited as one of the major stumbling blocks in the sustainable expansion of contract farming in many developing countries.This paper examines farmers’contract breach decisions from the perspective of time preferences.The empirical analysis is based on a household survey and economic field experiments of poultry households participating in contract farming conducted in Jiangsu Province,China.A discounted utility model and a maximum likelihood technique are applied to estimate farmers’time preferences and the effect of time preferences on contract breach in the production and sales phases are explored with a bivariate probit model.The results show that,on average,the poultry farmers in the sample are generally present biased and impatient regarding future utility.The regression results show that farmers with a higher preference for the present and a higher discount rate are more likely to breach contracts,and time preferences play a greater role in the production phase than in the sales phase.When considering heterogeneity,specific investments and transaction costs promote contract stability only for farmers with a low degree of impatience.Moreover,compared with large-scale farmers,small-scale farmers’contract breach decisions are more significantly affected by their time preferences.These results have implications for contract stability policies and other issues that are impacted by the linking of behavioral preferences to agricultural decisions.

A Floating Astronomical Time Scale for the Early Late Cretaceous Continental Strata in the Songliao Basin, Northeastern China

A continuous terrestrial succession was recovered from the Songke-2(SK-2)borehole in the Songliao Basin,Northeastern China.This borehole provides a unique material for further research on the continental paleoclimate during Cretaceous greenhouse period,following a series of achievements of the Songke-1(SK-1)core.In this study,thorium(Th)logging data were chosen as a paleoclimate proxy to conduct a detailed cyclostratigraphic analysis.The Th series varies quasi-periodically;power spectra and evolutionary fast Fourier transformation(FFT)analysis reveal significant cycles in the Quantou(K2 q),Qingshankou(K2 qn),Yaojia(K2 y)and Nenjiang(K2 n)formations.The ratio of cycle wavelengths in these stratigraphic units is approximately 20:5:2:1,corresponding to long orbital eccentricity(405 kyr),short orbital eccentricity(100 kyr),obliquity(37 kyr),and precession cycles(22.5 kyr and 18.4 kyr).The durations of the K2 n,K2 y,K2 qn and K2 q are estimated as 6.97,1.83,5.30 and 4.52 Myr,respectively,based on the constructed^18.62 Myr"floating"astronomical time scale(ATS).Comparison of the durations between the SK-1 s and SK-2 boreholes exhibits a slight difference of 0.06 Myr and 0.459 Myr for K2 qn and K2 y.Nevertheless,our ATS of K2 n supports the chronostratigraphic frame constructed by the CA-ID-TIMS data of the SK-1 s borehole.This new"floating"ATS provides precise numerical ages for stratigraphic boundaries,biozones and geological events in the Songliao Basin,and can serve as a basis for correlation of strata and events between marine and terrestrial systems.

Factors Influencing the Emergency Medical Service Response Time for Cardiovascular Disease in Guangzhou, China

While emergency medical service (EMS) response time (ERT) is a major factor associated with the survival of patients with cardiovascular disease (CVD), relatively few studies have explored the factors associated with ERT. This study aimed to assess the current status of ERT and to identify the factors affecting ERT in patients with CVD in China. Between January 1, 2011 and December 31, 2015, EMS responses to CVD incidents in Guangzhou, China, were examined. The primary outcome was ERT, defined as the time from receipt of an emergency call to the arrival of paramedics on the scene. Factors associated with ERT were evaluated by multivariable logistic regression. A total of 44 383 CVD incidents were analysed. The median ERT was 12.58 min (interquartile range=9.98-15.67). Among the risk factors, distance (OR=13.73, 95% CI=11.76- 16.04), level of hospital (OR=1.57, 95% CI=1.40-1.75), and site of the incident (OR=1.53, 95% CI=1.38-1.69) were the top three significant factors affecting the ERT. Our results suggest that greater attention should be given to factors affecting the ERT. It is essential to make continuous efforts to promote the development of effective interventions to reduce the response time.

Distribution, residence time, autotrophic production, and heterotrophic removal of DOP in the Mirs Bay, northern South China Sea

The importance of dissolved organic phosphorus(DOP) as a potential nutrient source for primary producers in marine systems has been recognized for up to eight decades, but currently, the understanding of the biogeochemistry of DOP is in its infancy. In the present study, monthly data between 2000 and 2014 were used to analyze the temporal and spatial distributions of DOP in the Mir Bay, the northern South China Sea. The DOP residence time(TDOP) was also investigated using a simple regression analysis in combination with chlorophyll a(Chl a) measurements while excess DOP(ΔDOP), produced by the biogeochemical processes of autotrophic production and heterotrophic removal, was determined using a two-component mixing mass-balance model in combination with salinity measurements. The results showed that the DOP concentration was(0.017±0.010) mg/L higher in the surface-water compared with the bottom-water and higher in the inner Tolo Harbour and waters adjacent to Shatoujiao compared with the main zone of the bay. Although seasonal changes and annual variability in the DOP were small, the surface DOP concentration was higher in the wet season(April–September)than in the dry season(October–March) due to the impacts of seaward discharges and atmospheric deposition into the bay. Measurement and regression results showed that the DOP release rate from phytoplankton production was about 1.83(gP)/(gChl a) and the TDOP was about 7 d, which implied that the DOP cycle in the bay was rapid. The ΔDOP was calculated from the model to be about 0.000 mg/L in the main zone of the bay and about 0.002 mg/L in the inner Tolo Harbour and waters adjacent to Shaotoujiao, suggesting that the autotrophic production of DOP was almost balanced by the heterotrophic removal in the main zone of the bay and dominated in the inner Tolo Harbour and waters adjacent to Shaotoujiao. In conclusion, the Mirs Bay is very productive and fairly heterotrophic.

Homogenised Monthly and Daily Temperature and Precipitation Time Series in China and Greece since 1960

In this paper,we describe and analyze two datasets entitled“Homogenised monthly and daily temperature and precipitation time series in China during 1960–2021”and“Homogenised monthly and daily temperature and precipitation time series in Greece during 1960–2010”.These datasets provide the homogenised monthly and daily mean(TG),minimum(TN),and maximum(TX)temperature and precipitation(RR)records since 1960 at 366 stations in China and 56stations in Greece.The datasets are available at the Science Data Bank repository and can be downloaded from https://doi.org/10.57760/sciencedb.01731 and https://doi.org/10.57760/sciencedb.01720.For China,the regional mean annual TG,TX,TN,and RR series during 1960–2021 showed significant warming or increasing trends of 0.27℃(10 yr)^(-1),0.22℃(10 yr)^(-1),0.35℃(10 yr)^(-1),and 6.81 mm(10 yr)-1,respectively.Most of the seasonal series revealed trends significant at the 0.05level,except for the spring,summer,and autumn RR series.For Greece,there were increasing trends of 0.09℃(10 yr)-1,0.08℃(10 yr)^(-1),and 0.11℃(10 yr)^(-1)for the annual TG,TX,and TN series,respectively,while a decreasing trend of–23.35 mm(10 yr)^(-1)was present for RR.The seasonal trends showed a significant warming rate for summer,but no significant changes were noted for spring(except for TN),autumn,and winter.For RR,only the winter time series displayed a statistically significant and robust trend[–15.82 mm(10 yr)^(-1)].The final homogenised temperature and precipitation time series for both China and Greece provide a better representation of the large-scale pattern of climate change over the past decades and provide a quality information source for climatological analyses.

A Review of Comminution Age Method and Its Potential Application in the East China Sea to Constrain the Time Scale of Sediment Source-to-Sink Process

The East China Sea(ECS) is a river-dominated epicontinental sea, linking the Asian continent to the northwestern Pacific via the large rivers originating from Tibetan Plateau. The relevant huge influx of riverine detritus has developed unique sedimentary systems in the ECS during the Quaternary, offering ideal terrestrial archives for reconstructing Quaternary paleoenvironmental changes and studying land-sea interactions. Overall, two characteristic river systems dominate the sedimentary systems and sediment source to sink transport patterns in the ECS, represented by the Changjiang(Yangtze River) and Huanghe(Yellow River) for the large river system and Taiwan rivers for the small river system. Given this, the sediments derived from both river systems bear distinct features in terms of parent rock lithology, provenance weathering and sediment transport. Previous studies mostly focus on either the ‘source' discrimination or the ‘sink' records of the sedimentary system in the ECS, while the source to sink process linking the land and sea, in particular its time scale, has been poorly understood. Here we introduce a newly-developed dating technique, the ‘comminution age' method, which offers a quantitative constraint on the time scale of sediment transfer from its ultimate source to the final depositional sink. This novel method is of great significance for improving our understanding on the earth surface processes including tectonic-climate driven weathering, and sediment recycling in relation to landscape evolution and marine environmental changes. The application of comminution age method in the ECS will provide important constraints on sediment source-to-sink process and more evidences for the construction of late Quaternary paleoenvironmental changes under these unique sedimentary systems.

A new decomposition model of sea level variability for the sea level anomaly time series prediction

Rising sea level is of great significance to coastal societies;predicting sea level extent in coastal regions is critical.When carrying out predictions,the subsequences obtained using decomposition methods may exhibit a certain regularity and therefore can provide multidimensional information that can be used to improve prediction models.Traditional decomposition methods such as seasonal and trend decomposition using Loess(STL)focus mostly on the fluctuating trend of time series and ignore its impact on prediction.Methods in the signal decomposition domain,such as variational mode decomposition(VMD),have no physical significance.In response to the above problems,a new decomposition method for sea level anomaly time series prediction(DMSLAP)is proposed.With this method,the trend term in a time series can be isolated and the effects of abnormal sea level change behaviors can be attenuated.We decompose multiperiod characteristics using this method while maintaining the smoothness of the analyzed series.Satellite altimetry data from 1993 to 2020 are used in experiments conducted in the study area.The results are then compared with predictions obtained using existing decomposition methods such as the STL and VMD methods and time varying filtering based on empirical mode decomposition(TVF-EMD).The performance of DMSLAP combined with a prediction method resulted in optimal sea level anomaly(SLA)predictions,with a minimum root mean square error(RMSE)of 1.40 cm and a maximum determination coefficient(R^(2))of 0.93 during 2020.The DMSLAP method was more accurate when predicting 1-year data and 3-year data.The TVF-EMD and DMSLAP methods had comparable accuracies,and the periodic term decomposed by the DMSLAP method was more in line with the actual law than that derived using the TVF-EMD method.Thus,DMSLAP can decompose SLA time series better than existing methods and is an effective tool for obtaining short-term SLA prediction.

New Zircon U-Pb Age of the Babu Ophiolites in Southeast Yunnan,China and Constrains of Plate Subduction Time

Objective The Babu ophiolite in Malipo County of southeastern Yunnan is interpreted as remanant ocean crust and represents a possible branch of Paleo-Tethyan Ocean in South China. It consists mainly of mafic and ultramafic rocks. These rocks are very important to understand the evolution of the Paleo-Tethyan Ocean. However, the Babu ophiolite is still disputed and the mafic and ultramafic rocks have been inferred to be part of the Emeishan large igneous province （LIP） by some researchers. In this paper, we present zircon U-Pb data on the metabasalts in Malipo to reveal the formation time of mafic and ultramafic rocks and their tectonic nature.

Hydrodynamic characteristics of a typical karst spring system based on time series analysis in northern China

In order to study the hydrodynamic characteristics of the karst aquifers in northern China,time series analyses(correlation and spectral analysis in addition with hydrograph recession analysis)are applied on Baotu Spring and Heihu Spring in Jinan karst spring system,a typical karst spring system in northern China.Results show that the auto-correlation coefficient of spring water level reaches the value of 0.2 after 123 days and 117 days for Baotu Spring and Heihu Spring,respectively.The regulation time obtained from the simple spectral density function in the same period is 187 days and 175 days for Baotu Spring and Heihu Spring.The auto-correlation coefficient of spring water level reaches the value of 0.2 in 34-82 days,and regulation time ranges among 40-59 days for every single hydrological year.The delay time between precipitation and spring water level obtained from cross correlation function is around 56 days for the period of 2012-2019,and varies among 30-79 days for every single hydrological year.In addition,the spectral bands in cross amplitude functions and gain functions are small with 0.02,and the values in the coherence functions are small.All these behaviors illustrate that Jinan karst spring system has a strong memory effect,large storage capacity,noticeable regulation effect,and time series analysis is a useful tool for studying the hydrodynamic characteristics of karst spring system in northern China.

Time Series Analysis of Energy Intensity, Value Added Tax and Corporate Income Tax: A Case Study of the Non-Ferrous Metal Industry, Jiangxi Province, China

Unprecedented industrialization and urbanization have led to China’s poor energy efficiency. In response, the Chinese government has set goals to reduce energy consumption that may include implementing new tax policies. In this paper, we investigate the relationship between energy intensity, an indicator that measures the efficiency of energy consumption, and two sources of government revenue in China (i.e., value-added tax (VAT) and corporate income tax). As a case study, we developed a Granger co-integration model to analyze the dynamic relationship of energy intensity, VAT and corporate income tax in the non-ferrous metal industry, Jiangxi Province, China, between 1996 and 2010. Augmented Dickey-Fuller tests were used to validate the model. In our time series analyses, we found when controlling for corporate income tax, a one log unit increase of VAT resulted in a decrease of 1.17 log units of energy intensity. However, when controlling for VAT, a one log unit increase of corporate income tax resulted in an increase of 0.34 log units of energy intensity. Understanding the relationship between energy intensity and taxation in industries that consume high volumes of energy can greatly enhance China’s goal to reduce energy consumption. We believe our findings add to this on-going discussion.

New Evidence of Detrital Zircon Ages for the Final Closure Time of the Paleo-Asian Ocean in the Eastern Central Asian Orogenic Belt(NE China)

Objective The NE China is located in the eastern segment of the Central Asian Orogenic Belt（CAOB）,which is a large accretionary orogen between the Siberian Craton and the North China Craton（NCC）.Many researches have discussed about the evolution of the Paleo-Asian Ocean（PAO）in the eastern CAOB.However,

China Daily ＆ The New York Times语言风格的对比

《China Daily》是中国国家英文日报，创刊于1981年，全球期均发行80余万份，其中，海外期均发行50余万份《中国日报》作为中国了解世界、世界了解中国的重要窗口，是国内外高端人士首选的中国英文媒体，是唯一有效进入国际主流社会、国外媒体转载率最高的中国报纸。《The New York Times》是一份在羡香港协成行集团国纽约出版的报纸；在全世界发行，有相当的影响力。美国有影响的英文对开日报。1851年9月18日创刊。由纽约时报公司在纽约出版。原名《纽约每渣时报》，1857年9月14日改用现名。

Preliminary research and scheme design of deep underground in situ geo-information detection experiment for Geology in Time

The deep earth,deep sea,and deep space are the main parts of the national“three deep”strategy,which is in the forefront of the strategic deployment clearly defined in China’s 14th Five-Year Plan(2021-2025)and the Long-Range Objectives Through the Year 2035.It is important to reveal the evolutionary process and mechanism of deep tectonics to understand the earth’s past,present and future.The academic con-notation of Geology in Time has been given for the first time,which refers to the multi-field evolution response process of geological bodies at different time and spatial scales caused by geological processes inside and outside the Earth.Based on the deep in situ detection space and the unique geological envi-ronment of China Jinping Underground Laboratory,the scientific issue of the correlation mechanism and law between deep internal time-varying and shallow geological response is given attention.Innovative research and frontier exploration on deep underground in situ geo-information detection experiments for Geology in Time are designed to be carried out,which will have the potential to explore the driving force of Geology in Time,reveal essential laws of deep earth science,and explore innovative technologies in deep underground engineering.

Energy return on investment, energy payback time, and greenhouse gas emissions of coal seam gas(CSG) production in China: a case of the Fanzhuang CSG project

The studies and development of coal seam gas（CSG） have been conducted for more than 30 years in China, but few of China＇s CSG projects have achieved large-scale commercial success; faced with the boom of shale gas, some investors are beginning to lose patience and confidence in CSG. China currently faces the following question： Should the government continue to vigorously support the development of the CSG industry？ To provide a reference for policy makers and investors, this paper calculates the EROI_（stnd）[a standardized energy return on investment（EROI） method], EROI_（ide）（the maximum theoretical EROI）, EROI_（3,i）（EROI considering the energy investment in transport）, and EROI_（3,1＋e）（EROI with environmental inputs） of a single vertical CSG well in the Fanzhuang CSG project in the Qinshui Basin. The energy payback time（EPT） and the greenhouse gas（GHG） emissions of the CSG systems are also calculated. The results show that over a 15-year lifetime, EROI_（stnd）, EROI_（ide）, EROI_（3,1）, and EROI_（3,1＋e）are expected to deliver EROIs of approximately11：1, 20：1, 7：1, and 6：1, respectively. The EPT within different boundaries is no more than 2 years, and the life-cycle GHG emissions are approximately 18.8 million kg CO_2 equivalent. The relatively high EROI and short EPT indicate that the government should take more positive measures to promote the development of the CSG industry.

Region-time-length algorithm and its application to the study of intermediate-short term earthquake precursor in North China

The Region-Time-Length Algorithm (RTL algorithm) is introduced and improved in the paper. Compared with the original definition, the influence of rupture length on RTL function is emphasized and the weights of epicentral distance function, time function, and rupture length function are ensured to be equal. The retrospective examinations of RTL algorithm in North China have indicated that the anomalies obtained by the improved RTL algorithm show the short or intermediate-short term precursory features in most cases. There are two types of RTL anomalous patterns before the main shock. For the I-type, the variation pattern of the VRTL, numerical values of the VRTL(x, y, z, t) function, is complete and most of them have shown the changing pattern of rising from 0 turning dropping or dropping from 0 turning rising. For the II-type, the variation pattern of VRTL is not complete, which increases or decreases quickly from 0 and there is no evident turning, the main shock generally occurs in the short period around the peak VRTL. The rising of VRTL indicates an increase of seismic activity relative to the background level, which means the enhancement of seismic activity, while the dropping of VRTL indicates the decrease of seismic activity relative to the background level, which represents the seismic quiescence to a certain extent. According to statistical examination results of RTL algorithm in North China, the methods to distinguish the intermediate and short-term anomalies and to estimate the occurrence time of the coming main shock are given in the paper. For both I and II-type RTL anomalies, the R-value, i.e., the forecasting score, is about 0.6 and 0.3 for the 3 months forecasting period and about 0.7 and 0.4 for the 6 months forecasting period. The preliminary discussion is also made for the influences of characteristic time-span t0, characteristic distance r0, and threshold magnitude M0 on computation of VRTL, as well as some other significant problems in application.

Winter Wheat Yield Estimation Based on Sparrow Search Algorithm Combined with Random Forest:A Case Study in Henan Province,China

Precise and timely prediction of crop yields is crucial for food security and the development of agricultural policies.However,crop yield is influenced by multiple factors within complex growth environments.Previous research has paid relatively little attention to the interference of environmental factors and drought on the growth of winter wheat.Therefore,there is an urgent need for more effective methods to explore the inherent relationship between these factors and crop yield,making precise yield prediction increasingly important.This study was based on four type of indicators including meteorological,crop growth status,environmental,and drought index,from October 2003 to June 2019 in Henan Province as the basic data for predicting winter wheat yield.Using the sparrow search al-gorithm combined with random forest(SSA-RF)under different input indicators,accuracy of winter wheat yield estimation was calcu-lated.The estimation accuracy of SSA-RF was compared with partial least squares regression(PLSR),extreme gradient boosting(XG-Boost),and random forest(RF)models.Finally,the determined optimal yield estimation method was used to predict winter wheat yield in three typical years.Following are the findings:1)the SSA-RF demonstrates superior performance in estimating winter wheat yield compared to other algorithms.The best yield estimation method is achieved by four types indicators’composition with SSA-RF)(R^(2)=0.805,RRMSE=9.9%.2)Crops growth status and environmental indicators play significant roles in wheat yield estimation,accounting for 46%and 22%of the yield importance among all indicators,respectively.3)Selecting indicators from October to April of the follow-ing year yielded the highest accuracy in winter wheat yield estimation,with an R^(2)of 0.826 and an RMSE of 9.0%.Yield estimates can be completed two months before the winter wheat harvest in June.4)The predicted performance will be slightly affected by severe drought.Compared with severe drought year(2011)(R^(2)=0.680)and normal year(2017)(R^(2)=0.790),the SSA-RF model has higher prediction accuracy for wet year(2018)(R^(2)=0.820).This study could provide an innovative approach for remote sensing estimation of winter wheat yield.yield.

A Time of“China Opportunity”will Benefit the World

It is very difficult to comprehend the macroeconomic model of China due to its economic complexity.This stems from a) uneven economic development between the eastern and western parts of the country;and b) her typical dualistic economic structure. As a result,China’s economic development has been plagued by various contradictions.To

Brief History of Xu-style Garden in the Middle Ancient Times of China

According to ancient books and documents,this paper collected and sorted out the people and things related to Xu-style gardens in the middle ancient period of Chinese history,during the 400 years from the division of“Three Kingdoms”to the unifi cation of Sui Dynasty.For the frequent war chaos,gardening constructions in Xuzhou were hardly seen in this period,but the gardening fruits of Xu-style garden had spread all over the country with a large number of Xu people moving south.While inheriting the splendid and rough style of Qin and Han Dynasties,Xu-style garden attached more importance to“spectacular”,summarized and put forward the ideas of“master nature”and“artistic conception”,and raised the gardening technique to a theoretical height,thus pioneered the idea of“master nature”in Chinese classical gardens.