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1.
目的:调查哈尔滨市盲校生目前致盲情况及致盲性原因。方法:应用眼科常规方法时99名盲校学生(去除无眼球者共196眼)进行全面检查。时致盲原因进行分析。结果:致盲性眼病中居第一位为先天性白内障手术后仍未脱盲者,未脱盲原因包括:术后严重并发症、手术时机太晚形成严重弱视者,共45眼(占22.96%);居第二位为视网膜、黄斑变性,共32眼(占16.33%);居第三位为视神经萎缩,共24眼(占12.25%)。结论:本次对哈尔滨市盲校学生致盲原因调查表明,第一位为先天白内障术后由于合并症及并发症仍未脱盲者;第二位为为视网膜、黄斑变性;第三位为视神经萎缩。提示眼病的早期诊断和得当治疗的重要性。  相似文献   
2.
目的:探讨重症监护病房(ICU)长期机械通气患者撤机困难的原因及撤机死亡的影响因素。方法:对2015年6月至2018年10月我院收治的80例长期机械通气患者的临床资料进行回顾性分析,按照患者撤机结果分为撤机成功组52例和撤机困难组28例,根据患者存活情况分为存活组59例和死亡组21例。比较各组临床资料,分析撤机困难的原因及撤机死亡的影响因素。结果:撤机困难组年龄、心功能不全比例、多器官功能障碍(MODS)比例、呼吸机相关肺炎(VAP)比例、肝功能不全比例、肾功能不全比例、血尿素氮显著高于撤机成功组,机械通气时间、气管切开时间显著长于撤机成功组,血清白蛋白显著低于撤机成功组(P0.05)。死亡组年龄、合并糖尿病比例、心功能不全比例、MODS比例、VAP比例、肝功能不全比例、肾功能不全比例、血尿素氮显著高于存活组,机械通气时间、气管切开时间显著长于存活组,血清白蛋白显著低于存活组(P0.05)。多因素Logistic回归分析显示:年龄、合并糖尿病、MODS、VAP、机械通气时间、气管切开时间、血清白蛋白是ICU长期机械通气患者撤机死亡的影响因素(P0.05)。结论:患者治疗期间发生脏器功能不全或器官功能衰竭、机械通气时间较长、气管切开时间较长、营养状态较差是长期机械通气患者撤机困难的主要原因,年龄、合并糖尿病、MODS、VAP、机械通气时间、气管切开时间、血清白蛋白是ICU长期机械通气患者撤机死亡的影响因素。  相似文献   
3.
Recent publications and political assessments point to the ongoing loss of global biological diversity. Identifying entry points for improved biodiversity policies requires us to improve our knowledge on the complex, anthropogenic factors that lead to biodiversity loss. This article approaches this challenge by analysing the causes and effects that experts from Peruvian political regions connect to biodiversity loss. In four workshops, 219 experts from 20 Peruvian political regions were asked to discuss the problem in focus groups. Besides observing the focus group discussions, meaning and context of mentioned aspects was further clarified in individual interviews.Performing a qualitative content analysis the aspects collected in focus groups have been clustered into groups of causes (environmental changes, economic land use issues, human expansion, ignorance and unawareness and weak political structures) and effects (environmental effects, loss of ecosystem services, economic effects and negative feedback effects). The results section presents all causes and effects in their local socio-economic context. Discussing the relevance of the results for policy making, I propose structuring the assessment of the biodiversity governance process in political output, social outcome and ecological impact to both highlighting the causal linkage of those dimensions and tracking the step-wise progress. This way, I break down the complex problem of biodiversity loss into tangible aspects and relate them to specific processes of economic development. I conclude that learning from regional experts and practitioners can help finding local approaches to improve policy processes under given capacities and conditions.  相似文献   
4.
Helicobacter pylori (H. pylori) infection is etiologically associated with gastric cancer and peptic ulcer diseases which are both important public health burdens which could be largely eliminated by H. pylori eradication. However, some investigators urge caution based on the hypothesis that eradication of H. pylori may result in an increase in the incidence of gastroesophageal reflux disease, esophageal adenocarcinoma, and childhood asthma. The ethnic Malays of northeastern Peninsular Malaysia have long had a low prevalence of H. pylori infection and, as expected, the incidence of gastric cancer and its precursor lesions is exceptionally low. The availability of a population with a low H. pylori prevalence and generally poor sanitation allows separation of H. pylori from the hygiene hypothesis and direct testing of whether absence of H. pylori is associated with untoward consequence. Contrary to predictions, in Malays, erosive esophagitis, Barrett's esophagus, distal esophageal cancers, and childhood asthma are all of low incidence. This suggests that H. pylori is not protective rather the presence of H. pylori infection is likely a surrogate for poor hygiene and not an important source of antigens involved in the hygiene hypothesis. Helicobacter pylori in Malays is related to transmission from H. pylori‐infected non‐Malay immigrants. The factors responsible for low H. pylori acquisition, transmission, and burden of H. pylori infection in Malays remain unclear and likely involves a combination of environmental, host (gene polymorphisms), and strain virulence factors. Based on evidence from this population, absence of H. pylori infection is more likely to be boon than a bane.  相似文献   
5.
BackgroundCurrent knowledge of the validity of registry data on prostate cancer-specific death is limited. We aimed to determine the underlying cause of death among Danish men with prostate cancer, to estimate the level of misattribution of prostate cancer death, and to examine the risk of death from prostate cancer when accounting for competing risk of death.Material and methodsWe investigated a nationwide cohort of 15,878 prostate cancer patients diagnosed in 2010–2014; with 3343 deaths occurring through 2016. Blinded medical chart review was carried out for 670 deaths and compared to the national cause of death registry. Five death categories were defined: 1) prostate cancer-specific death, 2) other unspecified urological cancer death, 3) other cancer death 4) cardiovascular disease death, and 5) other causes of death. Competing risk analyses compared Cox cause-specific and Fine-Gray regression models.ResultsChart review attributed 51.2% of deaths to prostate cancer, 17.0% to cardiovascular disease, and 16.7% to other causes. The Danish Register of Causes of Death attributed 71.7% of deaths to prostate cancer when including all registered contributing causes of death, and 57.0% of deaths when including only the primary registered cause of death. The probability of death by prostate cancer was 10% at 2-year survival.ConclusionsMore than half of the deceased men in our study cohort died of their prostate cancer disease within a mean of 2.4 years of follow up. Data from the death registry is prone to misclassification, potentially overestimating the proportion of deaths from prostate cancer.  相似文献   
6.
观察了云南蓝果树(Nyssa yunnanensis)种子的形态,并初步研究了萌发基质、光照、人工破坏内果皮和pH梯度碱液处理对云南蓝果树种子萌发的影响。结果表明:云南蓝果树种子(带内果皮)平均大小为0.94cm×0.52cm×0.17cm(长×宽×厚),千粒重约234.3g,有萌发瓣;红土/腐殖土/泥炭土(v/v/v,1∶1∶1)为云南蓝果树种子萌发的适宜基质;种子在光、暗条件下都能萌发;人工破坏内果皮能明显地提高种子的萌发率;碱液处理对云南蓝果树种子的萌发有抑制作用,但对中国蓝果树(N.sinensis)种子的萌发有促进作用。本文还对云南蓝果树的致濒原因进行了讨论。  相似文献   
7.
In Saudi Arabia, the construction industry has been growing remarkably during the past several years. However, the most hazardous worksites in the country may be found in this industry. This study identified the causes of accidents and injuries in the construction industry among 300 workers in Jeddah City, situated on the coast of the Red Sea. Results from the questionnaire showed that the major cause of accidents and injuries is the lack of awareness about occupational safety and lack of experience among the workers (>82%); and the most common type of accidents and injuries that occur in the construction industry, are workers falling from a height (>80%), and electrical shock (>60%). Recommendations to prevent accidents and injuries in this industry are provided in this paper.  相似文献   
8.
David Pfennig 《Oecologia》1990,85(1):101-107
Summary This study investigated the proximate basis of bimodally-distributed, environmentally-induced variation that occurs in natural populations of spade-foot toad tadpoles (Scaphiopus multiplicatus). Most individuals in most populations occur as a small, slowly-developing omnivore morph. In some of these same populations, a varying number of individuals occur as a large, rapidly-developing carnivore morph (Pfennig 1989). Censuses of 37 different natural ponds revealed that the frequency of the faster-developing carnivore morph correlated significantly positively with fairy shrimp density (their chief prey) and pond drying rate. By simultaneously varying two diet components and pond drying regime in artificial pools I found that only fairy shrimp density significantly affected the proportion of carnivores. Separate experiments established that the extent to which tadpoles developed the carnivore morphology correlated with shrimp density, and that morph determination depended on the ingestion of shrimp, not simply their presence. If a critical number of shrimp were ingested, the tadpole developed into a carnivore; if not, the tadpole developed by default into an omnivore. Thus a single cue — shrimp ingestion — triggers alternative ontogenetic trajectories. Using shrimp density to induce morph differentiation enables tadpoles to respond to their environment adaptively as shrimp are most abundant in highly ephemeral ponds, where the faster developing carnivores are favored.  相似文献   
9.

The latter half of the Paleozoic era is marked by notable evolutionary advances, followed by the greatest of all mass extinctions and the subsequent establishment of Mesozoic‐Cenozoic faunas of very different aspect. Current models suggest marked changes in concentration of oxygen and carbon dioxide in the Paleozoic atmosphere. Atmospheric oxygen is thought to have increased from 15% in the mid‐Devonian to near 35% by the end of the Carboniferous, followed by a decline to 17% near the end of the Permian. Atmospheric carbon dioxide was near 0.5% in the early Paleozoic, declining to less than 0.3% in the Devonian, and then more steeply downward to a minimum near 0.04% at the end of the Carboniferous. The principal causes of these changes were the advent and expansion of land plants, deposition of carbonates and continental weathering. Notwithstanding quantitative uncertainties, it seems clear that a major pulse of high oxygen concentration and associated shifts in carbon dioxide characterized the late Paleozoic atmosphere. Atmospheres with such different compositions have markedly different physical characteristics. These changes have major implications for the physiologies of contemporary organisms. The fossil records of various taxa indicate dramatic changes in the biosphere that coincide in time with the inferred changes in composition of the atmosphere. Major changes in phenotype observed in numerous lineages of animals and plants, including accelerated radiations in fresh water and on the land, are inferred to have occurred in response to these changes in the atmosphere. The morphologies, physiologies, and inferred behavior of many organisms preserved in the fossil record are in good accord with expectations based on hyperoxic, low carbon dioxide conditions of the Carboniferous atmosphere and with a return to lower oxygen levels by the end of the Permian.  相似文献   
10.
信阳市发生的干旱主要有伏旱、秋旱和冬旱3种类型,且夏季发生干旱的频率远高于其它季节。干旱的成因除季风环流、地形地貌、地下水资源因素外,还有水利排灌设施不健全、农业生产结构与作物布局不合理、工业生产规模扩张等社会经济因素。本文在利用Pa法分级统计旱灾发生频次、总结旱灾发生规律的基础上,提出了有针对性的防御对策。  相似文献   
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