Inland China Research Articles

Government Provides Vigorous Supports to the Improvement of Health Care in Qinghai Province, China.

Qinghai province is located in the northeastern part of the Tibetan Plateau, and is an underdeveloped province of inland China. Chinese government gives high priority to the improvement of the wellbeing of Qinghai people, and have provided great supports in aspects of policy, funding, and professional resource to the development of health care and medical system in Qinghai. Great progress has been made, and wellness of residents in Qinghai has been significantly improved. This article reviews the strategies and measures from central and provincial government in improving health care of Qinghai province under the leadership of the Communist Party of China.

Individual particle investigation on the chloride depletion of inland transported sea spray aerosols during East Asian summer monsoon

Inland transported sea spray aerosol (SSA) particles along with multiphase reactions are essential to drive the regional circulation of nitrogen, sulfur and halogen species in the atmosphere. Specially, the physicochemical properties of SSA will be significantly affected by the displacement reaction of chloride. However, the role of organic species and the mixing state on the chloride depletion of SSA during long-range inland transport remains unclear. Hence, a single particle aerosol mass spectrometer (SPAMS) was employed to investigate the particle size and chemical composition of individual SSA particles over inland southern China during the East Asian summer monsoon. Based on the variation of chemical composition, SSA particles were clustered into SSA-Aged, SSA-Bio and SSA-Ca. SSA-Aged was regarded as the aged Na-rich SSA particles. In comparison to the SSA-Aged, SSA-Bio involved some extra organic species associated with biological origin (i.e., organic nitrogen and phosphate). Each type occupies for approximately 50% of total detected SSA particles. Besides, SSA-Ca may relate to organic shell of Na-rich SSA particles, which is negligible (~3%). Tight correlation between Na and diverse organic acids was exhibited for the SSA-Aged (r2 = 0.52, p < 0.01) and SSA-Bio (r2 = 0.61, p < 0.01), reflecting the impact of organic acids to the chloride displacement during inland transport SSA particles. The chloride depletion occupied by organic acids is estimated to be up to 34%. It is noted that distinctly different degree of chloride depletion was observed between SSA-Aged and SSA-Bio. It is more likely to be attributed to the associated organic coatings for the SSA-Bio particles, which inhibits the displacement reactions between acids and chloride. As revealed from the mixing state of SSA-Bio, defined hourly mean peak area ratio of Cl / Na increases with the increasing phosphate and organic nitrogen. This finding provides additional basis for the improvement of modeling simulations in chlorine circulation and a comprehensive understanding of the effects of organics on chloride depletion of SSA particles.

The evolutionary mechanism of China's urban network from 1997 to 2015: An analysis of air passenger flows

To reveal the complexity of China's urban network, this paper proposes an empirical approach to examining the evolutionary mechanism of, rather than just mapping, the spatial pattern of the Chinese urban network from 1997 to 2015. The results show that the Chinese urban network is a complex structure that is embedded in China's unique context, where two interwoven processes, namely, globalization and decentralization, have shaped the network's spatial pattern. Moreover, the Chinese urban network is shifting from a single-core structure, with Beijing as its center, towards a diamond structure, anchored by the four ‘national centers’ of Beijing, Shanghai, Guangzhou, and Chengdu. Along with the transformation of their network structure, Chinese cities are interacting more closely and frequently. The results of the exponential random graph model (ERGM) show that the two interconnected forces, namely, globalization and decentralization, have tremendous impacts on the evolution of the Chinese urban network. Specifically, the uneven decentralization has a complex effect on the evolution of China's urban network in terms of a polarization-trickle-down-repolarization process. And the integration of inland China into the process of globalization has a significant effect on the connectivity of Chinese cities and causes a significant rise of central and western cities within the Chinese urban network.

Monthly variations in mercury exposure of school children and adults in an industrial area of southwestern China

Recent studies have shown that rice consumption can be the major pathway for human methylmercury (MeHg) exposure in inland China. However, few studies have considered the susceptible population of school children's exposure through rice ingestion. In this study, monthly variations in total Hg (THg)/MeHg concentrations in rice, fish, hair, and urine samples were studied to evaluate the Hg (both THg and MeHg) exposure in Guiyang, a typical industrial area with high anthropogenic emission of Hg. A total of 17 primary school (school A) students, 29 middle school (school B) students, and 46 guardians participated in this study for one year. Hair THg, hair MeHg, and urine THg concentrations ranged from 355–413 ng g−1, 213–236 ng g−1, and 469–518 ng g−1 Creatinine (ng·g−1 Cr), respectively, and no significant differences were observed between different genders and age groups. Hair and urine Hg concentrations showed slightly higher values in the cold season (October to February) than the hot season (March to September), but without significant difference. High monthly variability of individual hair and urine Hg concentrations suggested that long-term study could effectively decrease the uncertainty. The school students showed significantly higher urine THg concentrations than adults due to children's unique physiological structure and behaviors. Probable daily intake (PDI) of MeHg via rice and fish ingestion averaged at 0.0091, 0.0090, and 0.0079 μg kg−1 d−1 for school A students, school B students, and their guardians, respectively, which means that 86%, 84%, and 87% of the PDI were originated from rice ingestion, respectively. Therefore, more attention should be paid to children as a susceptible population. The results indicated low risk of Hg exposure via rice and fish consumption for urban residents in a Chinese industrial city.

The semi-diurnal cycle of deep convective systems over Eastern China and its surrounding seas in summer based on an automatic tracking algorithm

Deep convective systems (DCSs) are associated with severe weather events and can affect regional and global climate. To study the semi-diurnal variation of DCSs over Eastern China and its surrounding seas in summer, we modified the Tracking of Organized Convection Algorithm through a 3-D segmentatioN (TOOCAN) by employing Himawari-8 operational cloud property (CLP) products instead of original infrared images, and renamed the algorithm as TOOCAN-CLP. The DCSs detected over land and sea are divided into small-, medium-, and large-sized classes based on the convective core equivalent radius. The small and medium-sized DCSs over land exhibit a maximum occurrence in the afternoon, which is associated with local thermal instability and sea breeze circulation. The occurrence of small DCSs over the tropical sea areas varies analogously to that of small continental DCSs but with a smaller amplitude. However, medium-sized DCSs over the sea, which account for the majority of DCSs over the sea, exhibit weak semi-diurnal variability. Large DCSs over inland China and its surrounding seas tend to initiate at night and decay in the daytime. The generation of large DCSs over inland China at night is mainly due to the enhanced transport of warm and moist air by strong large-scale prevailing southerly or southwesterly winds, while the large offshore DCSs accompanied by heavy rainfall is closely associated with the interaction between local offshore breeze and large-scale monsoon flows, as well as gravity waves.

The impact of regional market integration and economic opening up on environmental total factor energy productivity in Chinese provinces

China is the world's largest energy consumer; how can Chinese limited energy resources ensure a continuous development of its economy? This paper examines the impact of China's market integration and economic opening up on the Environmental Total Factor Energy Productivity (ETFEP) of 29 provinces in China for the period 1999–2017 and have the following findings: (1) China should strengthen its resource management in improving its ETFEP by providing indispensable impetus for ETFEP to turn from negative to positive growth and, meanwhile, making technological progress to bring about a two-wheel drive mode. (2) The key to improving Chinese ETFEP lies in inland China. The inland region should take over the industries transferred from coastal areas in a scientific manner, and avoid falling into the poverty accumulation trap of “being behind→introducing→lagging behind→introducing again→and falling behind again”. (3) Coastal areas should achieve the goal of increasing its ETFEP by speeding up its market integration, matching the higher economic opening up situation of the coastal areas. The key to improving the ETFEP of the inland areas is to focus on inter-regional market integration and the priority of this integration should be placed over the economic opening up, which seems more realistic at this stage.

A Critical-Holistic Approach to the Place-Specific Geographies of Inhabited River Islands on the Rural-Urban Fringe of Inland China

A Critical-Holistic Approach to the Place-Specific Geographies of Inhabited River Islands on the Rural-Urban Fringe of Inland China

Characterization of black carbon aerosol in the Yangtze River Delta, China: Seasonal variation and source apportionment

As a crucial absorptive component of aerosols, black carbon (BC) plays a key role in modifying the planetary boundary layer (PBL) meteorology and hence aggravating the haze pollution. In this study, using the seven-channel Aethalometer model AE-33, the equivalent BC aerosols were continuously observed for one year in a typical city of Nanjing in the Yangtze River Delta (YRD). Together with the pollutant data of PM2.5 and trace gases (NO2, SO2, CO and O3), and the methods of potential source contribution function (PSCF) and concentration weighted trajectory (CWT) models, the spatiotemporal distribution and source apportionment of BC mass concentrations in Nanjing are discussed. It had large discrepancies in monthly and seasonal variations of BC concentrations, which were found to be the highest in December (3109.4 ± 1875.0 ng m−3) and the lowest in September (1300.8 ± 1031.6 ng m−3). Meanwhile, the BC concentrations ranked in the order of winter (2619.5 ± 1576.8 ng m−3) > spring (2142.4 ± 1219.3 ng m−3) > summer (1645.6 ± 1229.7 ng m−3) > autumn (1583.1 ± 1333.1 ng m−3). The diurnal variation of BC exhibited bimodal distributions in four seasons, peaking at 07:00–09:00 and 20:00–23:00, respectively. Fossil fuel BC (BCff) was calculated to contribute 71–77% to BC concentration. Long-range transport of BC was noticed mainly across inland China of North China Plain (NCP) and Twain-Hu regions in winter, and from the eastern YRD and southern PRD regions in summer. Overall, BC in Nanjing mainly originated from the surrounding cities in YRD, which had a maximum contribution more than 2000 ng m−3. The potential sources of BC varied significantly in the four seasons.

Economic growth and carbon emissions: Estimation of a panel threshold model for the transition process in China

In recent years, the correlation between economic growth and environmental pollution has become noticeably contentious in China, which is experiencing the process of transitions in various social and economic sectors, for example, slowing economic growth, reformations to industrial and capital structure, ongoing urbanization, aggravated aging population and a series of environmental challenges, which are also known as a “New Normal” era in the 2010s. In the present study, a test is conducted on the non-linear relationship between economy and environment, which are represented as real GDP (Gross Domestic Product) per capita and carbon emissions per capita, respectively. Based on the data of a non-dynamic panel that covers 30 Chinese provinces from 2001 to 2016, the threshold regression model is applied with fixed effects to understand how the mentioned transitions impact on such relationship as structural breaks, in particular since its “New Normal” era. In brief, according to the estimation results, economic growth with a sustained high level of investment in technology (e.g., Northwest and Southwest China) and environmental protection activities are of empirical significance to cutting down on carbon emissions in China. Moreover, given the emissions reduction during China’s economic growth, “Economically significant provinces” concentrated in East China (e.g., Beijing, Tianjin, Shanghai, Jiangsu and Shandong in the present study) ought to develop and transfer their energy structure in a more renewable manner. In the meantime, “Energy abundant provinces” located in inland China are supposed to develop clean mining technology and strengthen their construction of energy delivery channel, which complies with an efficient market mechanism for cross-regional transaction in renewable energy from the perspective of sustainability.

Effects of continental emissions on cloud condensation nuclei (CCN) activity in the northern South China Sea during summertime 2018

Abstract. Aerosol particles in marine atmosphere have been shown to significantly affect cloud formation, atmospheric optical properties, and climate change. However, high temporally and spatially resolved atmospheric measurements over the sea are currently sparse, limiting our understanding of aerosol properties in marine atmosphere. In this study, a ship-based cruise campaign was conducted over the northern South China Sea (SCS) region during summertime 2018. The chemical composition of non-refractory PM1 (NR-PM1), the particle number size distribution (PNSD), and size-resolved cloud condensation nuclei (CCN) activity were measured by a time-of-flight aerosol chemical speciation monitor (ToF-ACSM) and the combination of a cloud condensation nuclei counter (CCNc) and a scanning mobility particle sizer (SMPS). Overall, aerosol particles exhibited a unimodal distribution centering at 60–80 nm and the chemical composition of the NR-PM1 was dominated by sulfate (∼ 46 %), which likely originated from anthropogenic emissions rather than dimethyl sulfide (DMS) oxidation. Two polluted episodes (P1 and P2) were observed, and both were characterized by high particle number concentrations (NCN) which originated from local emissions and from emissions in inland China via long-range transport. The concentrations of trace gases (i.e., O3, CO, NOx) and particles (NCN and NCCN at ss = 0.34 %) were elevated during P2 at the end of the campaign and decreased with offshore distance, further suggesting important impacts of anthropogenic emissions from the inland Pearl River Delta (PRD) region. Two relatively clean periods (C1 and C2) prior to and after tropical storm Bebinca were classified and the air was affected by air masses from the southwest and from the Indo-Chinese Peninsula, respectively. Chemical composition measurements showed an increase in organic mass fraction during P2 compared to C2; however, no obviously different κ values were obtained from the CCNc measurements, implying that the air masses carried pollutants from local sources during long-range transport. We report an average value of about 0.4 for the aerosol hygroscopicity parameter κ, which falls within the literature values (i.e., 0.2–1.0) for urban and remote marine atmosphere. In addition, our results showed that the CCN fraction (NCCN∕NCN, tot) and the κ values had no clear correlation either with the offshore distance or with concentrations of the particles. Our study highlights dynamical variations in particle properties and the impact of long-range transport from continental China and the Indo-Chinese Peninsula on the northern SCS region during summertime.

A Patulous Progress: International Entrepreneurship Effects on Chinese Born-Global Firm Performance

Using data from SMEs in Hubei province, the role of entrepreneurship in the sustainable performance of born global firms in China was discussed. The structural equation modeling analysis of 345 questionnaires indicates that both international knowledge and international entrepreneurial capability are significantly related to born global firms’ performance. Dynamic capabilities, which includes three sub-dimensions: adaptation capability, absorption capability and innovation capability, was found to be less important to firm performance. Therefore, it may be argued that born global firms in inland China are still limited by resources, including those generated from the international knowledge needed to adapt to internal and external pressures.

Measurement of Radon Concentration and Estimation of Its Emission of Coal-Fired Power Plants

In the experiment, RAD7 multi-functional electronic radon meter was used to measure the radon (222Rn) concentration at key points in the production process of three typical coal-fired power plants in Hunan, Hubei and Jiangxi provinces along the Yangtze river in China. The results show that after the combustion of raw coal, the radon was released, which caused radon concentration after the boiler’s gas system to be significantly higher than the air intake. Combined with the measurement and survey data, two different estimation methods of radon emission were established. First, based on radon concentration measured on site and the air volume at each inlet and outlet, the normalized radon emission of three coal fired power plants are calculated to be 102 GBq/GWa order of magnitude. The second one is using activity concentration of 226Ra in combination with actual coal use to calculate the emission, in this way, that typical value of normalize radon emission 151.3 GBq/GWa is obtained. This study provides data support for the construction of nuclear power plants in inland China.

中国内陸における「増地不増収」の実態と農業経営的特質 : 内モンゴル自治区杭錦旗の事例をもとに

中国内陸における「増地不増収」の実態と農業経営的特質 : 内モンゴル自治区杭錦旗の事例をもとに

Temperature-induced dry climate in basins in the northeastern Tibetan Plateau during the early to middle Holocene

Ongoing global warming will have a significant impact on terrestrial water resources, especially in arid and semi-arid regions. Assessing changes in the hydrology and water resources in inland basins under a warm climate in the recent geological past can provide a valuable context for assessing their current and possible future status. Here we present a record from a rapidly-accumulating sediment core from Lake Dalianhai in the Gonghe Basin in the northeastern Tibetan Plateau. The chronology of the uppermost 51.63 m of the core is based on AMS 14C dates from 11 samples of terrestrial plant microfossils and 14 bulk samples. Hydroclimatic variations within the basin during the last 23,000 yr were reconstructed from sedimentological and geochemical parameters and paleoshoreline records. The results indicate that the Gonghe Basin experienced relatively arid conditions during 23,000-14,700 cal yr BP. Lake Dalianhai was refilled at 14,700 cal yr BP and a high lake level was sustained until the beginning of the Holocene, as indicated by changes in the concentration of OH-GDGTs. However, the lake level was low during the early to middle Holocene (11,700-4700 cal yr BP) and increased during the late Holocene. Based on a comparison with lake level records and aeolian sand deposits from the region, we conclude that the climate was extremely dry in basins in the northeastern Tibetan Plateau during the early to middle Holocene. We propose that strong evaporation combined with high summer temperatures during the early to middle Holocene were responsible for the dry climate at that time, rather than changes in mid-latitude precipitation. Given the situation occurred during the early to middle Holocene, ongoing global warming may seriously threaten water resources in inland China, even if precipitation increases substantially.

Spatiotemporal trends of atmospheric Pb over the last century across inland China

Sedimentary records from remote regions contain pollutants derived dominantly from atmospheric input, and thus have the potential to trace past atmospheric pollution history. Based on seventeen sediment records from relatively remote areas of China, atmospheric Pb pollution history during the last century was studied. These records suggest only occasionally slight pollution before ~1950 and display synchronous Pb enrichment processes since the 1950s, implying the start of widespread atmospheric Pb pollution in China. This corresponded well with the beginning of socio-economic development after the establishment of the People's Republic of China. However, owing to the Chinese Cultural Revolution, a roughly unchanged atmospheric Pb status was found in the 1960–70s except on the Qinghai-Tibetan Plateau, where atmospheric Pb still increased gradually caused by long-range atmospheric transport of pollutants from southwest Asia. In ~1980–2000, atmospheric Pb experienced the greatest increase, resulting from rapid development of extensive economy after the Reform and Opening-up in 1978. After ~2000, atmospheric Pb generally stopped increase due to the phasing out of leaded gasoline, but it remained high, with the highest in Southwest China, medium in Northeast China, central North China and the Qinghai-Tibetan Plateau, and the lowest in the southeast Mongolia Plateau and West China. This study reveals spatio-temporal variations of atmospheric Pb in inland China under the influence of recent human activities, providing an important supplement for understanding global Pb pollution in the Anthropocene.

Non-agricultural sources dominate the atmospheric NH3 in Xi'an, a megacity in the semi-arid region of China

Ammonia (NH3), as a dominant alkaline gas in the atmosphere, plays a vital role in Chinese urban haze formation process, but its source in urban areas of China is controversial. To identify the sources of urban NH3 in the semi-arid region of East Asia, real-time measurements of NH3 and NH4+ of PM2.5 in the urban atmosphere of Xi'an, inland China during the winter and summer of 2017 were performed and their stable nitrogen isotope composition were analyzed. NH3 was 38.0 ± 9.4 μg/m3 in the summer, which is 1.5 times higher than that in the winter. Concentration of NH3 in both seasons well correlated with that of PAHs in PM2.5 and the mass ratio of (BbF + BeP + IP + BghiP) to the total PAHs, suggesting that fossil fuel combustion is an important source of NH3 in Xi'an. Moreover, diurnal variation pattern of NH3 was consistent with that of CO in the summer, peaking in the morning and evening rush hours, respectively, further indicating an importance of the contribution of traffic emissions to NH3 in the city. Based on the source apportionment by using isotope mixing model, we found that 66.4% and 62.5% of NH3 in the urban atmosphere were contributed by non-agricultural sources in the summer and winter, respectively. Our work revealed that non-agricultural sources dominate the atmospheric NH3 of Xi'an, where haze pollution is still severe, and suggested that emission controls of non-agricultural NH3 could be an effective way to mitigate the air pollution problem in the semi-arid region of East Asia.

Increased human pressures on the alpine ecosystem along the Qinghai-Tibet Railway

Construction of the Qinghai-Tibet Railway (QTR) increased the links between inland China and the Qinghai-Tibet Plateau (QTP). The QTR accelerated surrounding tourism, boosted the local economy and led to rapid development of livestock raising. To assess how distance from the railway and different regions has influenced the impact of the QTR on the alpine ecosystem, human footprint maps were produced to indicate human pressures, and the normalized difference vegetation index (NDVI), an index of vegetation greenness, was used to characterize the growth of alpine vegetation. The construction and operation of the QTR have increased human pressures, while the establishment of nature reserves has effectively reduced human pressures. The QTR contributes significantly to the increased human pressures in the Tibetan region compared with the Qinghai region and exerts negative impacts on alpine vegetation. Although the warmer and wetter climate trend has proven beneficial in enhancing alpine vegetation greenness, the declining trend of alpine vegetation has been stronger in regions with more intensive human pressures, especially in the grazing areas and the tourist areas around Lhasa. These results suggest that the impact of the QTR on alpine vegetation in Tibet is greater than that in Qinghai and that the spatial extent of the indirect impact of the QTR in Tibet is confined to approximately 30 km from the railway. These results will provide guidance and a theoretical basis for the protection of the alpine environment on the QTP under intensified anthropogenic influence.

The characteristics of atmospheric brown carbon in Xi'an, inland China: sources, size distributions and optical properties

Abstract. To investigate the characteristics of atmospheric brown carbon (BrC) in the semiarid region of East Asia, PM2.5 and size-resolved particles in the urban atmosphere of Xi'an, inland China, during the winter and summer of 2017 were collected and analyzed for optical properties and chemical compositions. Methanol extracts (MeOH extracts) were more light-absorbing than water extracts (H2O extracts) in the optical wavelength of 300–600 nm and well correlated with nitrophenols, polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs (r &gt; 0.78). The light absorptions (absλ=365 nm) of H2O extracts and MeOH extracts in winter were 28±16 and 49±32 M m−1, respectively, which are about 10 times higher than those in summer, mainly due to the enhanced emissions from biomass burning for house heating. Water-extracted BrC predominately occurred in the fine mode (&lt; 2.1 µm) during winter and summer, accounting for 81 % and 65 % of the total absorption of BrC, respectively. The light absorption and stable carbon isotope composition measurements showed an increasing ratio of absλ=365 nm-MeOH to absλ=550 nm-EC along with an enrichment of 13C in PM2.5 during the haze development, indicating an accumulation of secondarily formed BrC (e.g., nitrophenols) in the aerosol aging process. Positive matrix factorization (PMF) analysis showed that biomass burning, fossil fuel combustion, secondary formation, and fugitive dust are the major sources of BrC in the city, accounting for 55 %, 19 %, 16 %, and 10 % of the total BrC of PM2.5, respectively.

A Multi-Criteria Decision Support Framework for Inland Nuclear Power Plant Site Selection under Z-Information: A Case Study in Hunan Province of China

To promote the development of nuclear power project in inland China, a specialized multi-criteria decision support framework is constructed for the site selection of inland nuclear power plants in this work. The best worst method (BWM), decision-making trial and evaluation laboratory (DEMATEL), and technique for order performance by similarity to ideal solution (TOPSIS) are integrated with Z-numbers, namely Z-BWM, Z-DEMATEL, and Z-TOPSIS. Z-BWM and Z-DEMATEL are combined to produce the weights of criteria, and an extended Z-TOPSIS is utilized to determine the ranking of all alternatives. Finally, a case study is performed in Hunan province to demonstrate the practicability of the proposed decision support framework. The robustness and feasibility of the proposed method are shown by an in-depth analysis of the decision results.

Motion Sickness Predictors in College Students and Their First Experience Sailing at Sea.

INTRODUCTION: Individual motion sickness susceptibility can be rapidly estimated by the motion sickness susceptibility questionnaire (MSSQ), but its stability is affected by various factors. The purpose of this study was to investigate the involved predictive factors of motion sickness screened with uniform samples of Chinese college students and to verify the individual susceptibility difference in marine navigation.METHODS: A total of 1051 college students (719 men, 332 women; mean age: 18.32 ± 0.65 yr) completed the MSSQ. Another 42 men (mean age: 21.12 ± 1.10 yr) took part in 2 separate voyages. MSSQ data were collected before sailing and Graybiel motion sickness questionnaire (GMSQ) data were collected within 24 h after sailing and 24 h before landing.RESULTS: The internal consistency of the MSSQ was 0.685. The mean subscore of the MSSQ-A (18.47 ± 19.49) was significantly higher than that of the MSSQ-B (12.69 ± 14.97). Women had significantly higher MSSQ scores (38.29 ± 33.49) than men (27.87 ± 30.27). The mean MSSQ score of the inland subjects (33.97 ± 33.35) was significantly higher than that of the coastal subjects (27.81 ± 29.24). Nearly 93% of new seafarers experienced seasickness during their first navigation. The MSSQ score was positively correlated with seasickness symptoms (r = 0.706).CONCLUSION: Gender, age, and birthplace appear to be important predictors of motion sickness for Chinese college students. Specifically, women, younger people, and people who were born in inland China seem more prone to the syndrome. A high MSSQ score is a risk factor for seasickness. However, long-term voyages can lead to habituation, which reduces the occurrence of seasickness.Zhang X, Sun Y. Motion sickness predictors in college students and their first experience sailing at sea. Aerosp Med Hum Perform. 2020; 91(2):71-78.