中外饭店区域集团化特征对比研究   总被引：7，自引：0，他引：7  

魏卫 《世界地理研究》2003,12(3):106-112

随着饭店业全球化进程的发展，饭店之间的竞争日趋激烈，国际饭店集团的出现使国际旅游市场和饭店业都发生了极大的变化。与中国饭店集团相比，国际饭店集团具有诸多竞争优势，本文将以世界饭店集团300强为例，与中国饭店区域集团化特征进行对比分析，从而为中国饭店业借鉴国际饭店集团成功经验，应对其挑战提供启示。  相似文献   

Habitat, occurrence and conservation of Saharo-Arabian-Turanian element Forsskaolea tenacissima L. in the Iberian Peninsula   总被引：1，自引：0，他引：1  

Javier Cabello  Domingo Alcaraz  Francisco Gmez-Mercado  Juan F. Mota  Javier Navarro  Julio Peas  Esther Gimnez 《Journal of Arid Environments》2003,53(4):491-500

The aim of this study is to assess the Iberian populations of Forsskaolea tenacissima L. according to its biogeographical interest, habitat, geographical range and conservation status. Results point out that they are restricted to gravel wadis of Tabernas Desert (SE Spain), are scarcely included in protected areas and represent historically isolated populations with relict behaviour. We also describe a new association, Senecioni-Forsskaoleetum tenacissimae. Conservation status of species is cause for concern and two conservation actions must be carried out. Firstly, protected areas should house Forsskaolea populations and secondly, phytosociological characterization of a community allows inventorying its habitat and directing conservation efforts to community level.  相似文献   

Sand harm in Taklimakan Desert highway and sand control     

HAN Zhiwen  WANG Tao  SUN Qingwei  DONG Zhibao  WANG Xunming 《地理学报》2003,13(1):45-53

Reputed as a wonderful achievement of the world's highway construction history, the Taklimakan Desert highway is now facing serious sand drift encroachment problems due to its 447- km-long passage of sand sea consisting of crescent dunes, barchan chains, compound transverse dune ridges and complex megadunes. To solve some technical problems in the protection of the highway from sand drift encroachment, desert experts have been conducting the theoretical and applied studies on sand movement laws; causes, severities and time-space differentiation of sand drift damages; and control ways including mechanical, chemical and biological measures. In this paper the authors give an overall summary on the research contents and recent progress in the control of sand drift damages in China and hold that the theoretical research results and practices in the prevention of sand drift encroachment on the cross-desert highway represent a breakthrough and has an epoch-making significance. Since the construction of protective forest along the cross-desert highway requires large amount of ground water, what will be its environmental consequence and whether it can effectively halt sand drift encroachment on the highway forever are the questions to be studied urgently.  相似文献   

Salt tolerance of Microcoleus vaginatus Gom., a cyanobacterium isolated from desert algal crust, was enhanced by exogenous carbohydrates     

Lanzhou Chen  Dunhai Li  Yongding Liu 《Journal of Arid Environments》2003,55(4):381

Microcoleus vaginatus isolated from a desert algal crust of Shapotou was cultured in BG-11 medium containing 0.2 mol l⁻¹ NaCl or 0.2 mol l⁻¹ NaCl plus 100 mg l⁻¹ sucrose, extracellular polymeric substances (EPS) or hot water-soluble polysaccharides (HWP), respectively. Photosynthetic oxygen evolution rates, photosystem II activity (Fv/Fm) and dark respiration of NaCl-stressed cells were enhanced significantly by the added sucrose or EPS under salt stress conditions (0.2 mol l⁻¹ NaCl). Compared with cells treated with salt alone, sodium contents in cells reduced significantly; the content of cellular total carbohydrate did not change, and intracellular sucrose, water-soluble sugar increased significantly following the addition of exogenous carbohydrates. Sucrose synthase (SS) activity of NaCl-stressed cells increased following the addition of sucrose, and sucrose phosphate synthase (SPS) activity of NaCl-stressed cells increased following the addition of exogenous sucrose, EPS or HWP compared with cells stressed with NaCl only. The results suggested that the extruded EPS might be re-absorbed by cells of M. vaginatus as carbon source, they could increase salt tolerance of M. vaginatus through the changes of carbohydrate metabolism and the selective uptake of sodium ions.  相似文献   

南天山西段古生代火山岩Ar-Ar年龄新资料   总被引：7，自引：0，他引：7  

龚福华  李曰俊  王清华  胡世玲  黄智斌  罗俊成 《高校地质学报》2003,9(3):494-498

根据新近采自中国南天山西段志留-泥盆系乌帕塔尔坎群中的安山岩样品和石炭-二叠纪康克林组上部英安岩角砾样品的全岩Ar-Ar定年测试,乌帕塔尔坎群安山岩的坪年龄为427.70±0.60 Ma,等时年龄为426.96±4.57 Ma; 康克林组上部的英安岩角砾的坪年龄为288.16±0.40 Ma,等时年龄为289.18±2.02 Ma.测试结果为研究中国南天山(西段)古生代造山带的构造体系提供了新的依据.  相似文献   

Distribution of L_g coda Q in the Chinese continent and its adjacent regions     

丛连理  胡家富  傅竹武  温一波  康国发  吴小平 《中国科学D辑(英文版)》2003,46(6)

In continent Lg is usually one of the predominant phases recorded by short-period or broad-band seismometers. A ray-theoretical approach shows that Lg wave is the superposition of higher-mode surface waves propagating in the continental crust[1—4]. The g…  相似文献   

《沉积学报》与中国沉积学的发展--贺《沉积学报》创刊二十周年     

刘宝珺 《沉积学报》2003,21(1):8-9

简要回顾了《沉积学报》创刊二十年对中国沉积学发展所产生的重要作用。  相似文献   

广东侨乡外向型经济优势及其地缘背景研究   总被引：1，自引：0，他引：1  

文云朝 《地理科学进展》1997,16(4):27-34

本文把广东侨乡外向型经济优势与广东籍华侨、侨人的地理分布及其地缘背景联系起来研究。它从地缘政治、地缘经济、地缘文化方面研究了影响地缘战略决策的基本要素，并结合东盟的具体情况对其进行分析、探讨，指出了面向21世纪再创侨乡优势的努力方向。  相似文献   

Ecophysiology of the saguaro cactus (Carnegiea gigantea) in the Saguaro National Monument: relationship to symptoms of decline     

Kate Lajtha  Kristin Kolberg  Jenna Getz 《Journal of Arid Environments》1997,36(4):579-590

The purpose of this study was to examine physiological correlates to the phenomenon of epidermal browning and saguaro decline in Saguaro National Monument. Gas exchange characteristics, surface temperatures, and the extent of epidermal browning in tissues of both healthy and declining saguaro cacti (Carnegiea gigantea) at different solar orientations were examined in eight long-term monitoring plots in the Rincon Mountain District of the Saguaro National Monument near Tucson, Arizona during both wet and dry seasons and years.Daily maximum surface temperatures were greatest on west-oriented tissues, as predicted by a simple model. However, south- and south-west-oriented tissues showed the highest browning indices, suggesting that browning may be more related to cumulative thermal loading than to extreme late afternoon temperature events. During the wet season, maximum nocturnal CO₂uptake rates and total nocturnal CO₂uptake were negatively correlated with browning index. Uptake rates during dry seasons and dry years was minimal, and not related to browning indices. However, healthy tissues of saguaros that also had tissues with high browning indices had wet-season maximum CO₂uptake rates as high as saguaros without damaged tissues, suggesting that the browning is not systemic but rather is tissue- and angle-specific. Instantaneous measures of water-use efficiency did not vary significantly or predictably by angle, but rather were greatest during night-time and in tissues when CO₂uptake was greatest. We suggest that browning symptoms on cacti are most likely due to natural abiotic stress, and are unrelated to systemic pollution stress or increased UV-B radiation.  相似文献   

山西太岳山种子植物区系特征     

柴宝峰  李毳 《山地学报》1997,(3)

调查的基础L，统计了太岳山种子植物有97科、316属、575种（含变种），分析了该区系的主要特征，即植物区系地理成分复杂，温带成分占优势；植物资源种类丰富，区系起源古老；植物区系具明显的过渡性；植被类型复杂，具明显的垂直分布．对该区野生经济植物进行了分类统计，为植物资源合理利用与生物多样性保护提供了基础资料穹科学依据．  相似文献