首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5篇
  免费   0篇
  2014年   1篇
  2011年   2篇
  2003年   1篇
  2002年   1篇
排序方式: 共有5条查询结果,搜索用时 15 毫秒
1
1.
Morphological convergence is a central concept in evolutionary biology, but convergent patterns remain under‐studied in nonvertebrate organisms. Some scallop species exhibit long‐distance swimming, a behaviour whose biomechanical requirements probably generate similar selective regimes. We tested the hypothesis that shell shape similarity in long‐distance swimming species is a result of convergent evolution. Using landmark‐based geometric morphometrics, we quantified shell shape in seven species representing major behavioural habits. All species displayed distinct shell shapes, with the exception of the two long‐distance swimmers, whose shells were indistinguishable. These species also displayed reduced morphological variance relative to other taxa. Finally, a phylogenetic simulation revealed that these species were more similar in their shell shape than was expected under Brownian motion, the model of character evolution that best described changes in shell shape. Together, these findings reveal that convergent evolution of shell shape occurs in scallops, and suggest that selection for shell shape and behaviour may be important in the diversification of the group. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163 , 571–584.  相似文献   
2.
3.
Fine-needle aspiration biopsy is recommended as the first and most important step in the management of nodular thyroid disease. A retrospective study of 520 patients with nodular thyroid disease was done in the north of Jordan, between January 1998 and August 2001. We compared the results of fine-needle aspiration biopsy (FNAB) of thyroid gland with postoperative histological findings. The results are classified into three groups A)-benign, B)-malignant, and C)-suspicious as shown in table II. The results of the FNAB were benign in 96.4% of the cases which include benign colloid nodules (325 cases), multi-nodular goitre (70 cases), diffuse goitre (40 cases), thyroiditis (23 cases) and thyroid cysts (43 cases). A total of 52 patients underwent surgical management, 49 patients found to be accurate with the FNAB. The accuracy of FNAB was 94% (49 patients out of 52), with a specificity of 99% and a sensitivity of 93%. Ultrasound findings showed that 65% (338 patients) had solid nodules, 15% (78 patients) had cystic lesions and 20% (104 patients) had mixed echogenicity lesions. Histological confirmation of malignancy was 10 out of 11 patients with a 91% accuracy rate. FNAB was found to be a highly effective procedure, which can obviate a lot of unnecessary surgery in case of thyroid lesions, and avoid over treatment of benign disease. Surgery was recommended in all suspicious cases. FNAB under ultrasound guidance increases the sensitivity rate which can reach 100%. FNAB accuracy seems to be similar in cold and in hot nodules. Clinically, most of the patients with benign colloid nodules were having goitres suggesting the role played by iodine deficiency is which a prominent feature in that area in Jordan.  相似文献   
4.
Fine-needle aspiration biopsy is recommended as first and most important step in the management of breast cancer. A retrospective study was realized on 420 patients that underwent fine-needle aspiration (FNAB) in comparison to 140 patients that underwent surgical management. The results of FNAB showed that 81% of the cases were benign with an accuracy of 93%, a specificity of 97% and a sensitivity of 92% compared to operative findings. The accuracy of FNAB depends on the expertise and experience of the cyto pathologist as well as the technical skills of the physician performing the biopsy. FNAB is showing to be a highly effective procedure which can obviate unnecessary surgery in breast suspected lumps, save time and money and patient anxiety. It is the effective method for distinguishing benign from malign breast lesions.  相似文献   
5.
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号