Chromosomal evidence for autotetraploidy in the Turnera ulmifolia complex (Turneraceae)

1991 ◽  
Vol 69 (6) ◽  
pp. 1302-1308 ◽  
Author(s):  
Joel S. Shore

The hypothesis that tetraploids of two taxonomic varieties of the Turnera ulmifolia complex, vars. elegans and intermedia, have had autopolyploid origins, was tested. Chromosome counts within each variety show that two cytotypes occur with somatic numbers of 2n = 10 and 2n = 20. Tetrapoloids of both var. intermedia and var. elegans have pollen fertility approximately 13% less than that of diploids. Synthetic tetraploids produced by colchicine doubling exhibit pollen fertilities virtually identical to those of the natural tetraploids. While diploids exhibited only bivalent formation, tetraploids showed varying frequencies of univalents, bivalents, trivalents, and quadrivalents. The chromosome pairing model of R. C. Jackson and D. P. Hauber (1982. Am. J. Bot. 69: 644–646) and a minor modification of the goodness-of-fit test for that model, were used to test the hypothesis of an autopolyploid origin. For four of the six populations studied meiotically, the data fit the model. The data indicate that the tetraploid cytotypes of T. ulmifolia vars. elegans and intermedia have had autopolyploid origins. Key words: Turnera ulmifolia, autotetraploid, chromosome pairing model.

1985 ◽  
Vol 27 (5) ◽  
pp. 538-541 ◽  
Author(s):  
K. C. Armstrong

Chromosome pairing in the amphiploid (8x) of 4x Bromus pumpellianus ssp. dicksonii × 4x B. inermis was compared with pairing in the F1 hybrids between natural octoploid cytotypes of B. inermis and B. pumpellianus and the octoploid parents. Predominantly bivalent pairing was found in both the amphioctoploid, octoploid F1 hybrids, and octoploid parents. Bivalent formation in the amphioctoploid could be based on chromosome differentiation between the tetraploid cytotypes of B. inermis and B. pumpellianus. These results suggest that the evolution of the octoploid cytotypes of B. inermis and B. pumpellianus could have involved hybridization of the tetraploid cytotypes.Key words: Bromus, chromosome pairing, octoploid, F1 hybrid, amphiploid.


2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
T Besbes ◽  
S Mleyhi ◽  
J Sahli ◽  
M Messai ◽  
J Ziadi ◽  
...  

Abstract Background Early prediction of patients at highest risk of a poor outcome after cardiovascular surgery, including death can aid medical decision making, and adapt health care management in order to improve prognosis. In this context, we conducted this study to validate the CASUS severity score after cardiac surgery in the Tunisian population. Methods This is a retrospective cohort study conducted among patients who underwent cardiac surgery under extracorporeal circulation during the year 2018 at the Cardiovascular Surgery Department of La Rabta University Hospital in Tunisia. Data were collected from the patients hospitalization records. The discrimination of the score was assessed using the ROC curve and the calibration using the Hosmer-Lemeshow goodness of fit test and then by constructing the calibration curve. Overall correct classification was also obtained. Results In our study, the observed mortality rate was 10.52% among the 95 included patients. The discriminating power of the CASUS score was estimated by the area under the ROC curve (AUC), this scoring system had a good discrimination with AUC greater than 0.9 from postoperative Day 0 to Day 5.From postoperative day 0 to day 5, the Hosmer-Lemeshow's test gave a value of chi square test statistic ranging from 1.474 to 8.42 and a value of level of significance ranging from 0.39 to 0.99 indicating a good calibration. The overall correct classification rate from postoperative day 0 to day 5 ranged from 84.4% to 92.4%. Conclusions Despite the differences in the profile of the risk factors between the Tunisian population and the population constituting the database used to develop the CASUS score, we can say that this risk model presents acceptable performances in our population, attested by adequate discrimination and calibration. Prospective and especially multicentre studies on larger samples are needed before definitively conclude on the performance of this model in our country. Key messages The casus score seems to be valid to predict mortality among patients undergoing cardiac surgery. Multicenter study on larger sample is needed to derive and validate models able to predict in-hospitals mortality.


Test ◽  
2021 ◽  
Author(s):  
Jiming Jiang ◽  
Mahmoud Torabi

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
T. Mesbahzadeh ◽  
M. M. Miglietta ◽  
M. Mirakbari ◽  
F. Soleimani Sardoo ◽  
M. Abdolhoseini

Precipitation and temperature are very important climatic parameters as their changes may affect life conditions. Therefore, predicting temporal trends of precipitation and temperature is very useful for societal and urban planning. In this research, in order to study the future trends in precipitation and temperature, we have applied scenarios of the fifth assessment report of IPCC. The results suggest that both parameters will be increasing in the studied area (Iran) in future. Since there is interdependence between these two climatic parameters, the independent analysis of the two fields will generate errors in the interpretation of model simulations. Therefore, in this study, copula theory was used for joint modeling of precipitation and temperature under climate change scenarios. By the joint distribution, we can find the structure of interdependence of precipitation and temperature in current and future under climate change conditions, which can assist in the risk assessment of extreme hydrological and meteorological events. Based on the results of goodness of fit test, the Frank copula function was selected for modeling of recorded and constructed data under RCP2.6 scenario and the Gaussian copula function was used for joint modeling of the constructed data under the RCP4.5 and RCP8.5 scenarios.


2021 ◽  
pp. 112972982110150
Author(s):  
Ya-mei Chen ◽  
Xiao-wen Fan ◽  
Ming-hong Liu ◽  
Jie Wang ◽  
Yi-qun Yang ◽  
...  

Purpose: The objective of this study was to determine the independent risk factors associated with peripheral venous catheter (PVC) failure and develop a model that can predict PVC failure. Methods: This prospective, multicenter cohort study was carried out in nine tertiary hospitals in Suzhou, China between December 2017 and February 2018. Adult patients undergoing first-time insertion of a PVC were observed from catheter insertion to removal. Logistic regression was used to identify the independent risk factors predicting PVC failure. Results: This study included 5345 patients. The PVC failure rate was 54.05% ( n = 2889/5345), and the most common causes of PVC failure were phlebitis (16.3%) and infiltration/extravasation (13.8%). On multivariate analysis, age (45–59 years: OR, 1.295; 95% CI, 1.074–1.561; 60–74 years: OR, 1.375; 95% CI, 1.143–1.654; ⩾75 years: OR, 1.676; 95% CI, 1.355–2.073); department (surgery OR, 1.229; 95% CI, 1.062–1.423; emergency internal/surgical ward OR, 1.451; 95% CI, 1.082–1.945); history of venous puncture in the last week (OR, 1.298, 95% CI 1.130–1.491); insertion site, number of puncture attempts, irritant fluid infusion, daily infusion time, daily infusion volume, and type of sealing liquid were independent predictors of PVC failure. Receiver operating characteristic curve analysis indicated that a logistic regression model constructed using these variables had moderate accuracy for the prediction of PVC failure (area under the curve, 0.781). The Hosmer-Lemeshow goodness of fit test demonstrated that the model was correctly specified (χ2 = 2.514, p = 0.961). Conclusion: This study should raise awareness among healthcare providers of the risk factors for PVC failure. We recommend that healthcare providers use vascular access device selection tools to select a clinically appropriate device and for the timely detection of complications, and have a list of drugs classified as irritants or vesicants so they can monitor patients receiving fluid infusions containing these drugs more frequently.


Statistics ◽  
2016 ◽  
Vol 50 (4) ◽  
pp. 750-774
Author(s):  
Taeyoon Kim ◽  
Cheolyong Park ◽  
Jeongcheol Ha ◽  
Zhi-Ming Luo ◽  
Sun Young Hwang

2013 ◽  
Vol 351 (3-4) ◽  
pp. 149-154
Author(s):  
Vilijandas Bagdonavičius ◽  
Mikhail Nikulin

Sign in / Sign up

Export Citation Format

Share Document