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51.
以华中师范大学的实践为例,介绍利用网上学位论文数据库资源来实现本校学位论文数据库回溯建库的一种便利快捷的建库方法。  相似文献   
52.
为了解重庆地区新型冠状病毒肺炎的流行过程与流行特征,为制订防治措施提供依据,收集了2020年1月24日-2月23日重庆市公共卫生医疗救治中心收治的主城区确诊新型冠状病毒肺炎病例223例的流行病学资料,进行回顾性分析.结果表明, 223例确诊病例平均年龄(46.5±16.1)岁;发病至首次就诊的平均间隔时间为6.0 d,发病至确诊的平均间隔时间为7.0 d,多数表现为普通型和轻型,无死亡病例;本地二代病例占近半数,聚集性病例占总病例的比例接近2/3.年龄、暴露史、基础性疾病与病情严重程度有统计学意义.由此可见重庆市主城区以聚集性病例为主,年龄与职业分布较广,从发病到就诊时间仍较长,重庆市防控策略对于疫情发展已产生良好的抑制作用.  相似文献   
53.
农产品流通码及追溯码的编码研究   总被引:1,自引:0,他引:1  
对国内一些省市农产品质量安全追溯系统进行调研,结合海南省重点科技计划项目“海南省热带农产品质量安全追溯系统研究”的经验,参照农业部发布的《NY/T1431—2007农产品追溯编码导则》标准,阐述农产品流通码及追溯码的编码知识。  相似文献   
54.
文章主要探讨了在使用《中国分类主题词表》进行回溯主题标引过程中,我们经常遇到而又容易标引错误的几个具体问题,并列举实例加以说明。  相似文献   
55.
立足于工作实践,从回溯建库工作的前期准备:制定规则、确定依据、设置流程和工作规范,到实践工作中遇到的实际问题的解决,就回溯建库工作中的问题进行详细论述。  相似文献   
56.
The justification for incorporating environmental effects into fisheries stock assessment models has been investigated and debated for a long time. Recently, a state‐space age‐structured assessment model which includes the stochastic change in the environmental covariate over time and its effect on recruitment was developed for Southern New England‐Mid Atlantic yellowtail flounder (Limanda ferruginea). In this paper, we first investigated the correlations of environmental covariates with Southern New England‐Mid Atlantic yellowtail flounder recruitment deviations. The covariate that was most strongly correlated with the recruitment deviations was then incorporated into the state‐space model and alternative effects on the stock‐recruit relationship were estimated and compared. For the model that performed best as measured by Akaike information criterion, we also compared the estimates and predictions of various population attributes and biological reference points with those from an otherwise identical model without the environmental covariate in the stock‐recruit function. We found that the estimates of population parameters are similar for the two models but the predictions differed substantially. To evaluate which model provided more reliable predictions, we quantitatively compared the prediction skill of the two models by generating two series of retrospective predictions. Comparison of the retrospective prediction pattern suggested that from an average point of view, the environmentally explicit model can provide more accurate near‐term recruitment predictions especially the one year ahead recruitment prediction. However, the accuracy of the near‐term recruitment prediction from the environmentally explicit model was largely determined by the accuracy of the corresponding environment prediction the model provides.  相似文献   
57.
Decadal change in abundance of surface migratory myctophid fishes was examined in the Kuroshio region of the western North Pacific for the 35 yr from 1957 to 1994 in relation to the Kuroshio regime shift, indicated by changes in its transport volume and sea surface temperature in the early 1970s. Each year, samples were collected from the 0‐ to 1‐m depth layer at night, from January to March, at 83 stations on average. Ten species belonging to five genera occurred. Juveniles [standard length (SL) ≤ 40 mm] and adults (SL > 40 mm) of each species were analysed. In juveniles, Myctophum asperum, M. nitidulum, Symbolophorus evermanni and Centrobranchus brevirostris accounted for 91.1% of the total catch (7419 individuals), while M. nitidulum contributed 82.4% of the total adult catch (494 individuals). The abundance of juvenile S. evermanni, C. brevirostris and M. nitidulum showed prominent peaks in 1971, together with adult M. nitidulum. These peaks corresponded to extraordinarily high zooplankton abundance in the Kuroshio region in 1971, suggesting high recruitment success and low adult mortality in surface migratory myctophids. Smaller changes in abundance in other years were species‐specific, and the fluctuation patterns were mainly explained by year‐to‐year fluctuations in the strength of the Kuroshio and the geographical distribution of each species, i.e. an increased Kuroshio flow volume resulted in an increase in tropical species and a decrease in temperate species, but no change in the pan‐Kuroshio species.  相似文献   
58.
This retrospective study assessed the diagnoses of emergency presentations and the survival to discharge of backyard chickens in five veterinary clinics within Australia. A total of 333 cases were reviewed from September 2019 to March 2022. October to December was the busiest period in both 2021 and 2020, with cases steadily increasing in the warmer months. Discharge following emergency presentation occurred in 57.4% of reviewed cases. Female chickens represented 92.7% of total cases, with an average age at presentation of 2.2 years (ranging from 1 day to 10 years). The most frequent diagnoses were of reproductive disease (n = 94/333), open diagnosis (n = 55/333), respiratory disease (n = 42/333), predator attack (n = 28/333), musculoskeletal disease (n = 22/333) and parasitism (n = 22/333).  相似文献   
59.
Objective: To describe the functional outcome of canine and feline survivors of cardiopulmonary arrest (CPA) and the clinical characteristics surrounding their resuscitation. Design: Retrospective study. Setting: Veterinary teaching hospital. Animals: Client‐owned dogs (15) and cats (3) with CPA. Interventions: None. Measurements and main results: Eighteen animals were identified to have survived to discharge following CPA. Cardiopulmonary arrest was associated with anesthesia with or without pre‐existing disease in 10 animals, cardiovascular collapse in 5 animals, and chronic disease with an imposed stress in 3 animals. All CPAs were witnessed in the hospital. The most common initial rhythm at CPA was asystole (72%). Return of spontaneous circulation (ROSC) was achieved in less than 15 minutes from the onset of cardiopulmonary cerebral resuscitation (CPCR) in all animals. No animals had a recurrence of CPA after the initial CPA. Animals were of a wide range of ages (0.5–16 years) and breeds. Two animals were neurologically abnormal at discharge, one of which was normal at 2 months following CPA. Conclusions: A good functional recovery after CPCR was documented in the small number of CPA survivors presented in this study. This may be due to the reversible nature of their inciting cause of CPA, early detections of CPA (‘witnessed’), and/or the animal's underlying normal health status.  相似文献   
60.
Johnsen  Kurt H.  Major  John E. 《New Forests》1998,15(3):271-281
Seedlings from 20 families of black spruce (Picea mariana (Mill.) B.S.P.), representing a large range in field productivity, were subjected to a greenhouse retrospective test under ambient (409 ppm – year 1, 384 ppm – year 2) and high (686 ppm – year 1, 711 ppm – year 2) atmospheric CO2 environments. After one and two growth cycles, seedling height and diameter growth significantly increased under elevated CO2. At the end of the experiment, seedlings grown under high CO2 had a mean above-ground dry weight of 48.77 g as compared to 26.36 g for seedlings grown under ambient atmospheric CO2. Families were a significant source of variation for all growth parameters. Although the family × CO2 environment interaction was not a statistically significant source of variation in the analysis of variance, the correlation between greenhouse and 15-year field height growth was weaker (r = 0.29, p = 0.2177) under elevated CO2 compared to ambient CO2 (r = 0.51, p = 0.0223) following the first growth cycle. However, following the second growth cycle, greenhouse-field correlations were similar between the two CO2 environments (ambient CO2: r = 0.55, p = 0.0115; elevated CO2: r = 0.56, p = 0.0101). Thus, with this set of families, growth performance ranking after two years appears relatively stable under ambient and elevated CO2.  相似文献   
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