社会转型时期的家庭与生产政治

在社会转型时期,土地不能满足农民家庭实现收支平衡的经济需求,农村家庭将经济生产空间转移到打工所在地区,农民工依赖出卖劳动力维持家庭的经济生产职能.工厂利用工人对工厂的这种依赖性和市场上劳动力过剩的形势,建立一系列与工人经济收入挂钩的管理体制,形成了工厂的专制主义体制.     

城市土地集约利用的内涵与结构解析

基于德国农业经营学派农业集约经营理论的借鉴与分析,论文对城市土地集约利用的内涵、影响因素、目标设定、形态结构进行了理论解析,将集约的目标锁定为"对土地资源的节约和土地利用效益提高",根据城市土地投入类型的差异,将"集约"解构成经济因子、土地因子和组织因子三大集约度.     

发展循环经济 实现草原畜牧业和谐发展

1、地区草原生态环境恶化的原因及治理现状 草原是半农半牧地区生态系统的主体,也是当地人民赖以生存和发展的物质基础.长期以来,受全球变暖、盲目开垦等因素的影响,半农半牧地区的生态环境遭受严重破坏,草原面积和草产量锐减,盐碱化日趋严重,不仅影响到草原畜牧业的发展,而且对当地人民生产和生活构成严重威胁.     

疏勒河流域移民安置工程对生态环境的影响

疏勒河流域处于河西走廊西部,气候干旱,生态环境十分脆弱,而随着人口的大量迁入,水土资源的大规模开发利用,会引起与地表水-地下水循环转化相关的生态环境变化.主要从水资源、耕地、人口、林地、草地、荒漠化土地方面的变化及其原因进行分析,研究移民工程对流域生态环境的影响.结果表明:疏勒河流域的水土资源开发利用总体趋势不断完善,人口与耕地、林地、草地、荒漠化土地具有正相关性,所以在以后的开发利用过程中,要以生态环境保护为出发点,以水土资源为核心,定发展、定绿洲、定林草,促进疏勒河流域生态环境的可持续发展.     

内蒙古中西部地区历史文化期的气候变迁与沙化

内蒙古中西部地区位于我国北部边疆,处于生态环境脆弱的农牧交错带上,自然演变的过程漫长且复杂,是灾害多发的地带,是极易土地沙化的区域,对各种自然和人为扰动极为敏感.在阐述内蒙古中西部地区气候形成概况的基础上,通过文献资料回顾了人类古代历史文化期的气候的变化与沙化情况.研究结果表明,历史上冷暖干湿气候差异性的交替运行,导致区域生态环境的波动变化和易灾、易沙化的趋势;气候的变化还通过早期人类活动的集聚格局,间接地影响了历史时期土地沙化的发展.     

聊城市自然资源动态及其与人口发展的关系

根据1999～2008年聊城市土地资源和人口的相关数据,采用自然资源承载力的研究方法,分析了聊城市自然资源与人口动态变化的关系.结果表明,耕地总体趋势下滑,林地、园地和城乡居民点与工矿用地缓慢增加,根据土地资源与人口的互动关系分析,得出聊城土地资源还能够承载市现有人口,但时森林资源和水资源造成很大的压力.     

贵州耕地资源变化与社会经济发展的相关性研究

利用 1983～2008 年贵州省长序列耕地统计数据以及相应的社会、经济资料,分析了该区域耕地资源数量动态变化趋势,运用逐步回归分析法,分析了耕地数量动态变化与社会经济因子之间的相关性.研究结果表明,贵州省耕地资源数量的突变在很大程度上是受国家政策的影响;由于人口基数大,人均耕地面积呈平缓递减趋势;土地利用率、耕地集约化利用程度不断提高,同时化肥、农药施用量也逐年增加,带来了生态环境的破坏;农村人口数、城市化水平对耕地资源数量变动的驱动作用非常明显.因此,必须控制人口数量,合理推进城市化进程,以促进贵州农村经济的可持续发展.     

河南省漯河市土地资源可持续利用研究

大地是人类赖以生存的物质基础.在当前人口日益增长、经济社会快速发展、生态环境压力逐渐增大的形势下,土地资源的可持续利用已经成为关系全局、影响深远的重大问题.以河南省漯河市为例,通过对土地资源利用现状的分析,结合经济社会发展需求和总体形势,探寻了典型平原农业区和城镇化、工业化快速推进区土地资源可持续利用的有效途径,可为土地利用和土地管理决策提供依据.     

城市化产生的城乡景观生态问题

运用景观生态学的理论和方法对城市化进程中的城市和乡村景观的结构、布局、功能和资源利用等方面进行研究,分析了中国目前由城市化带来的城乡景观问题和问题产生的原因:乡村景观生态问题突出自然、半自然景观的退化造成生态平衡失调,景观格局混乱造成生态环境质量下降,新旧景观不协调造成乡土特色消失,人地关系矛盾突出,土地浪费及污染严重,生态环境遭到破坏;城市景观生态问题强调区域生态环境遭到破坏使得生态功能下降、具有重要价值的自然与人文景观遭到破坏、城市绿色空间不断减少造成景观破碎度增加、城市布局缺乏规划引发空间发展问题.在此基础上提出相应的对策,指出乡村景观生态问题的解决应注重景观生态规划、调整布局,以整体性原则协调区域综合发展,有效协调各种矛盾,加大农村土地整理力度,开展生态网络建设;城市景观生态优化应着重于合理规划景观结构比例,建立合理的景观格局,并有效地建设城市绿地,调控生态环境.     

县域农村居民点用地集约利用评价研究——以南县为例

以南县乡镇为评价单元,从投入强度、利用程度、利用效率3个层面构建评价指标体系,采用因子分析法确定指标权重,综合指数法计算南县各乡镇的农村居民点用地集约度,并进行农村居民点用地集约利用分析评价,以期为南县农村居民点用地集约利用和持续发展提供政策依据.     

Causes of death and incidence of cancer in physicians and lawyers in Iceland

A retrospective study is accomplished in Iceland to study whether mortality and cancer incidence among male physicians (1,210) were lower than those among men of the general population and lawyers (1,032). Overall mortality among lawyers was similar to that of the general male population, however, mortality among the physicians was lower than that of the general population and the lawyers, due to lower mortality for all cancers (SMR 0.73), cerebrovascular diseases (SMR 0.53) and respiratory diseases (SMR 0.54). The physicians had higher mortality for suicide committed by drugs, solid or liquid substances. Cancer was not as frequent among the physicians as among the lawyers, particularly for lung cancer, the SIR was 0.45, but the rates were higher for cancer of the colon and brain among the physicians than among others.     

Pharmacokinetics and metabolism of vinyl fluoride in vivo and in vitro

Vinyl fluoride (VF) is an inhalation carcinogen at concentrations of 25 ppm or greater in rats and mice. The main neoplastic lesion induced in rodents was hepatic hemangiosarcomas, and mice were more sensitive than rats. In a first set of experiments, groups of three rats or five mice were exposed to VF in a closed-chamber gas uptake system at starting concentrations ranging from 50 to 250 ppm. Chamber concentrations of VF were measured every 10-12 min by gas chromatography. Partition coefficients were determined by the vial equilibration technique and used as parameters for a physiologically based pharmacokinetic (PBPK) model. Mice showed a higher whole-body metabolic capacity compared to rats (Vmax = 0.3 vs 0.1 mg/hr-kg). Both species had an estimated Km of < or = 0.02 mg/liter. The specificity for the oxidation of VF in vivo was determined by selective inhibition or induction of CYP 2E1. Inhibition with 4-methylpyrazole completely impaired VF uptake in rats and mice, whereas induction with ethanol (rats only) increased the metabolic capacity by two- to threefold. The pharmacokinetics of VF were also investigated in vitro. Microsomes from rat and mouse liver were incubated in a sealed vial with VF and an NADPH-regenerating system. Headspace concentrations (10-300 ppm) were monitored over time by gas chromatography. Consistent with the in vivo data, VF was metabolized faster by mouse microsomes than by rat microsomes (Vmax = 3.5 and 1.1 nmol/hr-mg protein, respectively). The rates of metabolism by human liver microsomes were generally in the same range as those found with rat liver microsomes (Vmax = 0.5-1.3 nmol/hr-mg protein), but one sample was similar to mice (Vmax = 3.3 nmol/ hr-mg protein). Metabolic rates in human microsomes were found to correlate with the amount of CYP 2E1 as determined by Western blotting and by chlorzoxazone 6-hydroxylation. It is concluded that the greater metabolic capacity of mice for VF both in vivo and in vitro may contribute to their greater susceptibility to tumor formation. CYP 2E1 is clearly the main isozyme involved in the oxidation of VF in all species tested. VF pharmacokinetics and metabolism in humans may depend upon the interindividual variability in the expression level of CYP 2E1. The excellent correspondence between in vivo and in vitro kinetics in rodents improves. substantially the degree of confidence for human in vivo predictions from in vitro data.     

Development and maintenance of bile canaliculi in vitro and in vivo

Four types of high-flux hemodialyzers, Primus 2000 (high-flux polysulfone 2.0 m2), Altra-Flux 170 G (cellulose diacetate 1.7 m2), FLX-15 GW (polyester-polymer alloy 1.5 m2) and PAN-85 DX (polyacrylonitrile 1.7 m2) were evaluated in vivo. A total of 12 stable chronic hemodialysis patients participated in the study and each type of dialyzer was tested once in 9 of them. Blood samples for the measurement of BUN, creatinine, phosphate, uric acid, albumin and beta2-microglobulin (beta2M) were drawn before and 5 min after the end of the study dialysis. During dialysis, which was performed in all patients with a blood flow rate of 250 ml/min for 240 min, the dialysate (550-600 ml/min) was collected every hour and samples were drawn for the measurements of all the above substances. The mean total amount of low-molecular substances removed per session by each dialyzer was very close to 19.5 g for urea, 2.0 g for creatinine, 0.9 g for phosphate and 1 g for uric acid. The one-third (30-33%) of the above amounts were removed during the first hour of dialysis. Dialyzers' clearances for creatinine and uric acid were significantly higher in Primus dialyzer comparing to FLX-15 GW (p < 0.05) while the clearance for urea showed a borderline significance (p = 0.055). No difference was found either among Altra-Flux 170 G, FLX-15 GW and PAN-85 DX or between Primus and PAN-85 DX dialyzers. Phosphate clearance did not show any difference among the four dialyzers. The lowest amount of albumin removed per session was 0.75 g by PAN-85 DX and the highest 1.8 g by FLX-15 GW, while the equivalents for beta2M were 80 mg by Altra-Flux 170 G and 142 mg by PAN-85 DX. A significant adsorption of beta2M on these dialysis membranes was indicated by the combination of a satisfactory serum beta2M reduction ratio (post-/predialysis values = 0.52, 0.77, 0.60, 0.55) with a reduced beta2M clearance (23.9, 13.6, 20.2, 25.1 ml/min). During the first hour of dialysis, in comparison to the following time, the highest amounts of albumin and beta2M (expressed as percentage of total) were removed by the Primus 2000 dialyzer. Our results indicate that under conventional conditions small differences in the surface area of the high-flux dialyzers are unimportant regarding the removal of low molecules. However, the composition of the membrane seems to play an important role in the removal of high-molecular substances.     

Smoking and pursuit of thinness in schoolgirls in London and Ottawa

It has been proposed that teenage girls often smoke cigarettes to protect themselves from the impulse to binge eat, with its feared weight-gain consequences, particularly when other measures such as greater dietary restraint have failed. The present study looked at the relationship between body mass index and standardised questionnaire responses concerning smoking, alcohol consumption, moods, weight changes, attitudes to body weight and shape, dietary patterns and menstruation in 1936 British (London) and 832 Canadian (Ottawa) schoolgirls. Data analysis revealed links between cigarette smoking and body weight/shape concerns, and awareness by subjects of these links; there was also a tendency for smokers in these two populations to be overweight but not grossly obese. Smoking was also related at all ages to being postmenarchal. The London population in particular revealed an association between smoking and a weight loss of 7 kg or more at some stage since puberty. Smoking was also linked, in a minority, with regular vomiting undertaken as a further defence against weight gain when overeating had occurred. These associations existed alongside the major and predictable association found between alcohol consumption and smoking. Similarities between the British and Canadian schoolgirls were striking in respect of rank order of reasons given for smoking and consequences of giving it up. Since smoking amongst older women is reportedly associated with below-average body weight it may indeed be effective in helping to curb weight gain. Our study provided little evidence of association between smoking and generalised anxiety or social anxiety (in either population), or depression (in the British cohort). We suggest that any preventive psychological approach to teenage female smoking should include attention to weight gain anxiety and consequent pursuit of thinness.     

Alterations in metabolism of H-epinephrine in the pregnant and non-pregnant state and in males

The influence of sex, pregnancy and parturition of biological accumulation and metabolic fate was studied in Sherman rats. 3H-epinephrine was used as a tracer to determine differences in metabolite formation in normal males and females as well as pregnant rats from 18 days post coitum to the end of parturition. The disappearance of 3H-epinephrine and its metabolites was measured in blood, heart, kidney and brain at different intervals but 20 min after the injection of tracer was found the most appropriate time to find appreciable radioactivity in most of the organs studied. All the comparisons for 3H-epinephrine accumulation and its transformation to metabolites have been reported 20 min post-perfusion period. Marked changes of high statistical significance in 3H-epinephrine accumulation and its transformation to 3H-metanephrine and 3H-acid metabolities were observed between males and females. Heart, adrenals, and spleen showed lower rate of metabolism but higher rate of accumulation during pregnancy. Kidney, ovary, and uterus demonstrated higher rate of metabolism but lower rate of accumulation during gestation. In brain regions, hypophysis discriminated greatly between males and females for the three parameters studied. There were important alterations in metabolite formation during 18 and 21 days of pregnancy. The observed variations have been considered due to modified endocrine activity during pregnancy and parturition.     

Comparative binding and toxicity of saxitoxin and saxitoxinol in mice and in cultured cells

The binding characteristics of saxitoxin (STX), a known voltage-gated sodium channel blocker, and its analog saxitoxinol (STXOL), were studied in neuroblastoma, peritoneal macrophage, hepatocytes and PC-12 cell lines. 3H-STXOL bound to the cell-surface sites which appear to be the same as those occupied by 3H-STX and which can, therefore, be identified as STX receptors. The relative agreement of respective Kd obtained by saturation, competition, association and dissociation kinetics for STX and STXOL suggest the absence of any artifact in binding measurements. Unlike STX, STXOL was non-toxic to mice by intratracheal instillation. The major advantage of using 3H-STXOL is that the tritium label is not exchangeable. Data from this study suggest that 3H-STXOL can be used to identify STX receptors at 37 degrees C.     

Response of Plasmodium falciparum to chloroquine and Fansidar in vivo and chloroquine and amodiaquine in vitro in Uganda

The response of P. falciparum to chloroquine and pyrimethamine-sulfadoxine in vivo and chloroquine and amodiaquine in vitro was investigated in parasitaemic school children from six locations. Mean parasite sensitivity to chloroquine at day 7 was 74% (range 61-97) with parasite clearance rates between 2-3 days and complete defervescence in 85% of febrile children. Sensitivity declined in the four sites followed up to day 14 to 45% (range 37-53). Parasites were significantly more sensitive to pyrimethamine/sulfadoxine at 5/6 sites (100% day 7) but 5% of subjects became parasitaemic by day 14. In vitro isolates were significantly less sensitive to chloroquine than to amodiaquine with a mean 99% effective concentration of 348 mumol/L compared to 6.44 mumol/L. Clearly the role of chloroquine as the primary therapy for uncomplicated P. falciparum malaria should be reconsidered especially in the light of increasing disease severity and resurgence. Amodiaquine may be suitable alternative with pyrimethamine/sulfadoxine as second line and for more severe malaria prior to referral. The cost of alternative antimalarials and the dynamic and deteriorating pattern of resistance are powerful arguments for more objective slide diagnosis to minimise drug pressure and a regular drug sensitivity surveillance system. We believe that the latter should concentrate on measuring clinical drug efficacy in symptomatic outpatients rather than in asymptomatic children while the former needs more pragmatic and economical strategies possibly centred on seasonality and risk.     

日本及世界的镁供需状况

叙述了日本镁工业的发展,日本向国外投资进口镁的情况,统计分析了日本及世界近几年的镁供需状况、消费结构和今后的镁供需预测。调查分析了今后几年世界汽车用镁的发展。     

Changes in and acceptance of surgical and noninvasive therapy procedures in cholecystolithiasis

BACKGROUND: The treatment of cholecystolithiasis has changed fundamentally in recent years due to the development of non-surgical techniques (extracorporeal shockwave lithotripsy [ESWL], oral litholysis) and the implementation of laparoscopic cholecystectomy. PATIENTS AND RESULTS: Retrospective analysis of 2270 patients (1649 women, 621 men; age: 47.2 +/- 14 years) presenting with gallstone disorders in a university medical outpatients department between 1988 and 1992 in order to be instructed as to the most suitable therapy method bear witness to the rapid change in therapeutic procedure. Laparoscopic removal of the gallbladder has virtually supplanted conventional cholecystectomy, and within 5 years the proportionate role of ESWL has declined from 21 to 12%. Over the years, the proportion of patients requiring no therapeutic intervention remained constant (at about 20%). The therapeutic recommendations of the "experts" were implemented in almost 80% of cases. The majority of patients were satisfied with the chosen therapeutic approach (surgery: 93.0%, ESWL: 77.6%), although 44% of ESWL-patients and 36% of surgically managed patients reported complaints which persisted even after completion of therapy. Despite unsuccessful ESWL (residual fragments or recurrent stones) 58/95 (61%) of interviewed patients would again give preference to this non-invasive modality in the event of a renewed therapeutic decision. CONCLUSION: Only a few years after its introduction, laparoscopic cholecystectomy has asserted itself as the predominant treatment option. But as far as acceptance and preference by the patient are concerned extracorporeal shockwave lithotripsy--as a non-invasive treatment modality--also enjoys high popularity and can be recommended as an alternative to surgery in suitable patients chosen according to the currently established stringent selection criteria.