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181.
湖南省野生果树资源的研究 总被引:8,自引:0,他引:8
1991-1996年对湖南省野生果树资源进行了研究,基本上摸清了该省野生果树资源的种类、分布及蕴藏量,计有209种及变种,隶属39属18科,并对主要种类的分布特点及蕴藏量进行了评价,为综合开发利用提供了依据。 相似文献
182.
183.
晚侏罗世蜥蜴化石在世界范围内分布较为贫乏,而这个时期的化石在研究早期蜥蜴类的形态及分类演化方面具有重要意义。记述了河北北部晚侏罗世蜥蜴化石一新属种:丽热河蜥Jeholacertaformosagen.etsp.nov.,该化石保存有大面积精美的皮肤鳞片。这是蜥蜴类鳞片化石在我国的首次发现,同时也为人类认识早期蜥蜴动物的表皮特征提供了珍贵的材料。由于躯干具有较大的方鳞,该蜥蜴应隶属于石龙子次亚目Scincomorpha,似可归入蜥蜴科Lacertidae,有待证实。模式标本采自河北平泉县杨树岭镇石门村义县组下部地层中,保存于中国地质博物馆。 相似文献
184.
采用聚类分析的方法,研究阐明在气候差异不明显的冲积平原区,农田杂草类型和相应的土壤类型(相当于土属)有明显的相关性。在划分旱地农田杂草类型时,环境条件的差异比栽培作物具有更重要的指示意义。由于杂草多为广布种,采用聚类分析的方法,比单纯用优势种能够更客观地划分杂草类型。 根据实地观测,指出了封丘地区危害严重的主要杂草种类和危害时间,以及不同环境条件下杂草的分布和危害程度,这对于农业生产上杂草的防除工作有一定指导意义。 相似文献
185.
广东省森林生态旅游与可持续发展 总被引:1,自引:0,他引:1
论述了森林生态旅游与森林生态旅游资源的内涵, 分析了广东省森林生态旅游的必要性、区位优势和资源优势, 提出了广东省森林生态旅游的原则与可持续发展措施。 相似文献
186.
A. Tagarelli A. Piro G. Tagarelli C. Valente 《International Journal of Anthropology》1999,14(2-3):147-151
In the present study, we have described and compared both the number and the types of the mistakes that were made during reading
of the Ishihara plates by 3,926 students attending the secondary schools in the province of Cosenza (Calabria, Southern Italy)
and by 546 Calabrian university students all without colour-blindness. There were no qualitative differences in the types
of mistakes made by the two groups of subjects during their reading of the Ishihara plates. Moreover, we have reported both
the mean frequencies and types of colour-blindness in only the province of Cosenza. During this study, it was shown that the
ishihara test is reliable during screenings for the diagnosis of colour vision deficiencies, as shown by some previous investigations. 相似文献
187.
188.
《Saudi Journal of Biological Sciences》2022,29(3):1306-1312
Background and objectiveCoronavirus Disease 2019 (COVID-19) has affected millions of individuals all over the world. In addition to the patients' compelling indications, various sociodemographic characteristics were identified to influence infection complications. The purpose of this study was to assess the impact of the aforementioned parameters on the dissemination of COVID-19 among residents of Saudi Arabia's Riyadh region.Materials and methodsIn the Saudi Arabian province of Riyadh, a cross-sectional retrospective analysis of COVID-19 incidences, recoveries, and case-fatality ratio (CFR) was undertaken. The study was carried out by gathering daily COVID-19 records from the ministry of health's official websites between October 2020 and September 2021. The influencing factors were obtained from the statistical authority. Using the SPSS IBM 25 software, the data was examined. The association between demographic factors as well as the presence of comorbidity on the COVID-19 outcome was determined using Spearman's correlation and regression tests. P < 0.05 was considered to indicate the significance of the results.ResultsThe data from the study indicated that the highest number of COVID-19 cases were recorded in June 2021, and peak recovery was observed in July 2021. The CFR declined progressively from October 2020 to just over 1, even when the cases peaked. A significant (p < 0.05) correlation between diabetes and COVID-19 incidences was observed. The recovery rate had a significant (p < 0.05) association with the literacy rate and those aged 14–49 years old. Presences of co-morbidities such as Dyslipidemia, hypertension, diabetes, asthma, stroke and heart failure have negatively affected the recovery from COVID-19 in the population. The CFR is significantly (p < 0.05) associated with people over 60, hypertensive patients, and asthma patients. Regression analysis suggested that the risk of complications due to COVID-19 infection is more in males, people above 60 years age and those suffering from co-morbidities.ConclusionsThe findings of the study indicate an association between several of the characteristics studied, such as gender, age, and comorbidity, and the spread of infection, recovery, and mortality. To restrict the spread of COVID-19 and prevent its complications, effective measures are required to control the modifiable risk factors. 相似文献
189.
本研究以采集于河北省小五台山自然保护区地卷属地衣为试验材料,通过形态解剖学、地衣次生代谢产物和nrDNA的ITS分子系统学分析,对地卷属地衣进行鉴定,发现小五台山分布地卷属1中国地衣新记录种——栗色地卷(新拟)(Peltigera castanea Goward, Goffinet & Mi?dl.)。该种的识别特征为:地衣体上表面灰褐色至暗褐色,中部稍具光泽;裂片顶端边缘稍具绒毛;粉芽颗粒状,褐色,并聚集成不规则圆形;下表面脉纹扁平,淡白色、淡褐色至淡黑色;假根密集,束状、丛生,上部呈柔毛状。 相似文献
190.
辽宁省主要农业自然灾害防御对策—林业生态工程建设框架 总被引:1,自引:0,他引:1
基于对辽宁省主要农业自然灾害发生与为害的分析和对林业生态工程建设科学积累的归纳总结,论证了防御农业自然灾害的对策——林业生态工程建设,具有防御多种自然灾害、发挥多种效益的功能和持久、稳定而易于建设的特点。以此为基础,根据主要农业自然灾害在辽宁省各地区的分布特点,在宏观上提出了辽宁省防御主要农业自然灾害的林业生态工程建设框架:在已有林业生态工程建设的基础上,继续开展以水土保持林为主的辽西林业生态工程建设,加强以农田防护林为主的辽中和辽北林业生态工程建设,大力开展以海防林为主的沿海地区林业生态工程建设,实施科学的辽东山区多样化森林经营方式,并以科技兴林保证林业生态工程建设这一总体布局的实施。同时简述了各项林业生态工程的具体实施方法。 相似文献