Statistical methods for paleodemography on fossil assemblages having small numbers of specimens: an investigation of dinosaur survival rates

Paleobiology ◽  
2011 ◽  
Vol 37 (1) ◽  
pp. 113-125 ◽  
Author(s):  
David Steinsaltz ◽  
Steven Hecht Orzack
Keyword(s):  
Survival Rate ◽  
Statistical Methods ◽  
Statistical Power ◽  
Survival Rates ◽  
Survivorship Curve ◽  
Size Dependent ◽  
Average Survival ◽  
Fossil Assemblages ◽  
Age Range ◽  
Number Of Individuals

We describe statistical methods to formulate and validate statements about survival rates given a small number of individuals. These methods allow one to estimate the age-specific survival rate and assess its uncertainty, to assess whether the survival rates during some age range differ from the survival rates during another age range, and to assess whether the survivorship curve has a particular shape. We illustrate these methods by applying them to a sample of 22 Albertosaurus sarcophagus individuals. We show that this sample is too small to provide any confidence in the claim that this species had a “convex” survivorship curve arising from age-specific survival rates that decreased monotonically with age. However, we show that a sample of 50 to 100 individuals has reasonable statistical power to support such a claim. There is evidence for the much weaker claim that average survival rates for ages 2 to 15 were higher than survival rates for later ages. Finally, we describe one way to account for size-dependent fossilization rates and show that a plausible positively-size-dependent fossilization rate results in a substantially non-convex survivorship curve for A. sarcophagus.

scholarly journals STUDY ON SURVIVABILITY OF NEWLY HATCHED LARVAE OF TWO SPECIES OF PEPPERMINT SHRIMP FED WITH DIFFERENT COMBINATIONS AND DENSITIES OF LIVE FOODS

2019 ◽  
Vol 14 (1) ◽  
pp. 15
Author(s):  
Indra Pratama ◽  
Hatim Albasri
Keyword(s):  
Survival Rate ◽  
Larval Stage ◽  
Survival Rates ◽  
The Third ◽  
Randomized Design ◽  
Average Survival ◽  
Peppermint Shrimp ◽  
Trial Treatment ◽  
Newly Hatched Larvae ◽  
Average Survival Rate

This study was aimed to evaluate different types and combinations of live foods in relation to the survivability of newly hatched Lysmata vittata and Lysmata intermedia larvae. The experiment consisted of three trials (different species, combinations, and densities of live foods) arranged in a completely randomized design. The first and second trials were subjected to L. vittata with three treatments for each trial (1A, 1B, 1C for trial-1; 1D, 1E, 1F for trial-2). The third trial consisted of two treatments (2A and 2B) tested on L. intermedia. Each treatment had three replicates. The results showed that the survival rates were low in all treatments. However, each treatment showed a significant effect (P<0.05) on the average survival rate of L. vittata and L. intermedia larvae. In the first trial, treatment 1C was the only one that had survived larvae after day 35 with 4.44% of final average survival rate (FASR). Four of the larvae reached the post-larval stage. In the second trial, treatment 1F showed a better condition than the other treatments with 5.56% FASR. Nevertheless, no larvae in the second trial had transformed to post-larval stage before the experiment ended at day 46. In the third trial, no larvae survived to reach the post-larval stage. In spite of this, treatment 2B had better daily average survival rate (DASR) than treatment 2A. This research concludes that the use of copepods as live food at an early larval stage and Artemia at a later stage is relatively more effective to improve the survival rate of peppermint shrimp larvae.

DEVELOPMENT OF AN INTRODUCTION PROTOCOL FOR STRAWBERRY PLANTS INTO IN VITRO CULTURE

2020 ◽  
Vol 5 (86) ◽  
pp. 45-50
Author(s):  
O.V. Mazneva ◽  
◽  
L.V. Tashmatova ◽  
T.M. Khromova ◽  
V.V. Shakhov ◽  
...  
Keyword(s):  
Survival Rate ◽  
In Vitro Culture ◽  
Plant Material ◽  
Survival Rates ◽  
Strawberry Plant ◽  
Active Growth ◽  
High Viability ◽  
Average Survival ◽  
Average Survival Rate

The research was conducted in order to develop an effective protocol for introducing strawberry plants into in vitro culture. The objects of the research were the most popular varieties of strawberries of domestic and foreign selection: Tsaritsa, Bereginya, Florence, Frida, Kimberly, etc. Mercurial preparations mertiolate at a concentration of 0.01% and sulema at a concentration of 0.1% were used as sterilizing agents. The isolation of explants was performed in several periods: the beginning of the growth was in February, active growth was in June, the decline of growth was in August. The studies have shown that the maximum aseptic cultures were obtained when processing strawberry plant material with mercurycontaining sulema preparation in the concentration of 0.1%. At the first stage of micropropagation, explants had a high viability during all periods of the isolation, the average survival rate for varieties was 74.8-80.7%. A significant influence of the genotype (varietal characteristics) on the survival rates of explants was noted. The number of explants suitable for cloning did not depend on the overall level of regeneration. Stabilization of the crop during winter introduction was much faster than in other periods. Using the winter term of the isolation of strawberry explants allowed to increase the yield of explants capable of further cloning, accelerate the stabilization of the culture in vitro and reduce the time for obtaining micro-plants suitable for planting in non-sterile conditions. On average, 75.2% of explants capable of further cloning for the varieties were obtained. As a result of the research, the conditions and methods for obtaining the largest number of viable sterile strawberry explants were worked out, which will be included into the process of reproduction in vitro and further research.

scholarly journals Survival of Single-Unit Porcelain-Fused-to-Metal (PFM) and Metal Crowns Placed by Students at an Australian University Dental Clinic over a Five-Year Period

2021 ◽  
Vol 9 (6) ◽  
pp. 60
Author(s):  
Chris Carey ◽  
Nick Del Din ◽  
Jessica Lamb ◽  
Hazel Wright ◽  
Nigel D. Robb ◽  
...  
Keyword(s):  
Survival Rate ◽  
Single Unit ◽  
Survival Rates ◽  
Dental Students ◽  
Cumulative Survival Rate ◽  
Dental Clinic ◽  
Cumulative Survival ◽  
Kaplan Meier ◽  
Average Survival ◽  
Clinical Records

The aim of this retrospective study was to determine the survival rate of single-unit porcelain-fused-to-metal (PFM) and metal crowns placed by dental students at an Australian university undergraduate dental clinic over a five-year period. Complications and the incidences of crown failures were recorded. Clinical records pertaining to single-unit PFM and metal crowns inserted over a five-year period were reviewed, including patient-related, tooth-related, and procedural factors for each crown. Crowns were evaluated as surviving, surviving with complications, or failed. Kaplan–Meier statistical analysis was used to estimate survival rate., This study is based on a sample of 232 (78.4%) PFM crowns and 64 (21.6%) metal crowns inserted between 2014 and 2018. Cumulatively, 224 (75.7%) were surviving, 48 (16.2%) were surviving but previously had complications, and 24 (8.1%) failed. The 5-year cumulative survival rate of all PFM and metal crowns was 83.9% (0.839 ± 0.038, Kaplan–Meier). The average survival time for all crowns was 4.432 ± 0.089 years. Comparatively, PFM crowns had a higher survival rate at 1 year (0.972 ± 0.010) and 2 years (0.919 ± 0.017), compared to metal crowns at 1 year (0.964 ± 0.011) and 2 years (0.894± 0.018). The survival rate of metal crowns remained constant from 2 years to 4 years and thereafter, whereas there was a continued decline in the survival rate of PFM crowns to 83.2% (0.832 ± 0.038) at 4 years and thereafter. Crowns placed on premolars had the highest cumulative survival rate whereas those placed on molars exhibited the lowest survival rate for the duration of the study period. Despite single-unit PFM crowns having a higher 1- and 2-year survival rate compared to metal crowns, metal crowns had a higher survival rate at 4 years and thereafter. Survival rates are comparable to previous studies.

Estimation of age-dependent survival rates of female tsetse flies (Diptera: Glossinidae) from ovarian age distributions

1999 ◽  
Vol 89 (6) ◽  
pp. 515-521 ◽  
Author(s):  
M. Jarry ◽  
J.P. Gouteux ◽  
M. Khaladi
Keyword(s):  
Growth Rate ◽  
Survival Rate ◽  
Survival Rates ◽  
Age Distribution ◽  
Likelihood Method ◽  
Tsetse Flies ◽  
Apparent Survival ◽  
Tsetse Control ◽  
Average Survival ◽  
Eigen Value

AbstractExisting attempts to estimate the survival rate of tsetse flies from ovarian age distributions generally assume that the population is stationary. The fact that the survival rate cannot be dissociated from the growth rate by these methods poses a problem. Under the assumption of a stable age distribution, we propose a maximum likelihood method to estimate the ‘apparent survival rate’ for three categories of females: nulliparous (β0), young parous (β1) and old parous flies (β2). The rate depends both on ‘real survival rates’ a0, a1 and a2, and a growth rate λ: β0 = a0/λ, β1 = a1/λ, and β2= a2/λ. We used a matrix model, which can be parameterized if the pupal survival rate and the pupal period are known. Replacing a0, a1 and a2 by β0,λ, β1λ, and β2λin the projection matrix, the problem amounts to calculating its dominant eigen-value λ, and hence a0, a1 and a2. The application to a field population of Glossina palpalis gambiensis Vanderplank in Burkina Faso showed there was a marked difference in survival rate according to age category. The average survival rate increased with age with decreasing variability. The results suggested that sampling (by trapping) may have had an effect on the dynamics of this tsetse population by ageing it artificially. This method may be a useful tool for monitoring tsetse control.

Survival of the Soybean Plants Depending on the Integrated Influence of Seeding Method and Seeding Rate in the Eastern Steppe of Ukraine

2019 ◽  
pp. 130-139
Keyword(s):  
Survival Rate ◽  
Survival Rates ◽  
Row Spacing ◽  
Seeding Rate ◽  
Plant Survival ◽  
Row Crops ◽  
Average Survival ◽  
Soybean Plants ◽  
Factor C ◽  
Average Survival Rate

The aim of the research was to establish the effect of the seeding rate and method of sowing on the future survival and density of soy plants before harvesting. The experiments were carried out during 2015–2018 in accordance with the generally accepted methodology. The experience was laid down according to the following scheme: factor A two soybean varieties: Baika and Annushka; factor B three variants of row spacing: 15, 45 and 70 cm; factor C five standards for sowing seeds: 0.8, 0.9, 1.0, 1.1 and 1.2 million pcs./ha. More favorable weather conditions for the growth and development of plants were formed in 2016, which ensured the formation of the highest density of soybean plants at the time of harvesting. The average survival rate of soybean plants this year was 84.8 %. The greatest density of plants before harvesting was on wide-row crops with 45 cm row-spacing. On average for years, on variants with 15, 45 and 70 cm row-spacing it was 68.6 pcs./m2, 70.3 and 64.7 pcs./m2, respectively. The large density of plants before harvesting on crops with 45 cm row-spacing was due to the higher field germination of seeds, and not to higher plant survival rates. Since, due to a more uniform distribution of plants over the feeding area, which ensured the row method of sowing, their survival was greatest on row crops. So, in the variants with row-spacing of 15, 45 and 70 cm, the average plant survival by years, varieties and seeding rates was 82.3%, 80.4 and 78.2%, respectively. The highest survival rates of soybean plants of the varieties Baika and Annushka were noted on row crops with the lowest seeding rate 0.8 million pcs./ha. The influence of the seeding rate on plant survival with its gradual increase by the same indicator 0.1 million pcs./ha increased. In particular, with its increase from 0.8 to 0.9 million pcs./ha, the average survival rate of soybean plants by varieties and methods of sowing decreased by 0.7%, while from 1.1 to 1.2 million pcs./ha by 1.3%. The influence of the sowing rate was large on the options with 70 cm row spacing. Thus, on an average over the years, the survival rate of soybean plants variety Annushka with an increase in the sowing rate from 0.8 to 1.2 million pcs./ha in crops with 15, 45 and row-spacing 70 cm decreased by 2.5, 3.2 and 4.5%, respectively. This trend was noted in all years of the experiments.

THE PRINTING OF PACIOLI'S SUMMA IN 1494: HOW MANY COPIES WERE PRINTED?

2007 ◽  
Vol 34 (1) ◽  
pp. 125-145 ◽  
Author(s):  
Alan Sangster
Keyword(s):  
Survival Rate ◽  
Survival Rates ◽  
Printing Process

This paper considers the printing of Pacioli's Summa de Arithmetica, Geometria, Proportioni et Proportionalita (Summa) in 1494. In particular, it attempts to answer the question, how many copies of Summa were printed in 1494? It does so through consideration of the printing process, the printer of Summa, the size of the book, survival rates of other “serious” books of the period, and the dates it contains revealing when parts of it were completed. It finds that more copies were published than was previously suggested, and that the survival rate of copies has probably as much to do with the manner in which it was treated once acquired as in the number of copies printed.

scholarly journals Survival after surgery among patients with cholangiocarcinoma in Northeast Thailand according to anatomical and morphological classification

BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Chaiwat Tawarungruang ◽  
Narong Khuntikeo ◽  
Nittaya Chamadol ◽  
Vallop Laopaiboon ◽  
Jaruwan Thuanman ◽  
...  
Keyword(s):  
Survival Rate ◽  
Survival Time ◽  
Median Survival ◽  
Median Survival Time ◽  
Cox Regression ◽  
Survival Rates ◽  
Care Program ◽  
Tumor Location ◽  
Northeast Thailand ◽  
Curative Surgery

Abstract Background Cholangiocarcinoma (CCA) has been categorized based on tumor location as intrahepatic (ICCA), perihilar (PCCA) or distal (DCCA), and based on the morphology of the tumor of the bile duct as mass forming (MF), periductal infiltrating (PI) or intraductal (ID). To date, there is limited evidence available regarding the survival of CCA among these different anatomical and morphological classifications. This study aimed to evaluate the survival rate and median survival time after curative surgery among CCA patients according to their anatomical and morphological classifications, and to determine the association between these classifications and survival. Methods This study included CCA patients who underwent curative surgery from the Cholangiocarcinoma Screening and Care Program (CASCAP), Northeast Thailand. The anatomical and morphological classifications were based on pathological findings after surgery. Survival rates of CCA and median survival time since the date of CCA surgery and 95% confidence intervals (CI) were calculated. Multiple cox regression was performed to evaluate factors associated with survival which were quantified by hazard ratios (HR) and their 95% CIs. Results Of the 746 CCA patients, 514 had died at the completion of the study which constituted 15,643.6 person-months of data recordings. The incidence rate was 3.3 per 100 patients per month (95% CI: 3.0–3.6), with median survival time of 17.8 months (95% CI: 15.4–20.2), and 5-year survival rate of 24.6% (95% CI: 20.7–28.6). The longest median survival time was 21.8 months (95% CI: 16.3–27.3) while the highest 5-year survival rate of 34.8% (95% CI: 23.8–46.0) occurred in the DCCA group. A combination of anatomical and morphological classifications, PCCA+ID, was associated with the longest median survival time of 40.5 months (95% CI: 17.9–63.0) and the highest 5-year survival rate of 42.6% (95% CI: 25.4–58.9). The ICCA+MF combination was associated with survival (adjusted HR: 1.45; 95% CI: 1.01–2.09; P = 0.013) compared to ICCA+ID patients. Conclusions Among patients receiving surgical treatment, those with PCCA+ID had the highest 5-year survival rate, which was higher than in groups classified by only anatomical characteristics. Additionally, the patients with ICCA+MF tended to have unfavorable surgical outcomes. Showed the highest survival association. Therefore, further investigations into CCA imaging should focus on patients with a combination of anatomical and morphological classifications.

scholarly journals The survival rates and risk factors of implants in the early stage: a retrospective study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yong Yang ◽  
Huiting Hu ◽  
Mianyan Zeng ◽  
Hongxing Chu ◽  
Zekun Gan ◽  
...  
Keyword(s):  
Risk Factors ◽  
Survival Rate ◽  
Dental Implants ◽  
Bone Quality ◽  
Early Stage ◽  
Survival Rates ◽  
Bone Augmentation ◽  
Early Survival ◽  
Immediate Implantation ◽  
Implant Length

Abstract Background Few large-sample studies in China have focused on the early survival of dental implants. The present study aimed to report the early survival rates of implants and determine the related influencing factors. Methods All patients receiving dental implants at our institution between 2006 and 2017 were included. The endpoint of the study was early survival rates of implants, according to gender, age, maxilla/mandible, dental position, bone augmentation, bone augmentation category, immediate implant, submerged implant category, implant diameter, implant length, implant torque, and other related factors. Initially, SPSS22.0 was used for statistical analysis. The Chi-square test was used to screen all factors, and those with p < 0.05 were further introduced into a multiple logistic regression model to illustrate the risk factors for early survival rates of implants. Results In this study, we included 1078 cases (601 males and 477 females) with 2053 implants. After implantation, 1974 implants were retained, and the early survival rate was 96.15%. Patients aged 30–60 years (OR  2.392), with Class I bone quality (OR  3.689), bone augmentation (OR  1.742), immediate implantation (OR  3.509), and implant length < 10 mm (OR  2.972), were said to possess risk factors conducive to early survival rates. Conclusions The early survival rate of implants in our cohort exceeded 96%, with risk factors including age, tooth position, bone quality, implant length, bone augmentation surgery, and immediate implantation. When the above factors coexist, implant placement should be treated carefully.

scholarly journals Efficient Cryopreservation of Populus tremula by In Vitro-Grown Axillary Buds and Genetic Stability of Recovered Plants

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 77
Author(s):  
Elena O. Vidyagina ◽  
Nikolay N. Kharchenko ◽  
Konstantin A. Shestibratov
Keyword(s):  
Survival Rate ◽  
Axillary Buds ◽  
Long Term Storage ◽  
Average Survival ◽  
Transgenic Lines ◽  
Ssr Loci ◽  
One Step ◽  
The One

Axillary buds of in vitro microshoots were successfully frozen at –196 °C by the one-step freezing method using the protective vitrification solution 2 (PVS2). Microshoots were taken from 11 transgenic lines and three wild type lines. Influence of different explant pretreatments were analyzed from the point of their influence towards recovery after cryopreservation. It was found out that the use of axillary buds as explants after removal of the apical one increases recovery on average by 8%. The cultivation on growth medium of higher density insignificantly raises the regenerants survival rate. Pretreatment of the osmotic fluid (OF) shows the greatest influence on the survival rate. It leads to the increase in survival rate by 20%. The cryopreservation technology providing regenerants average survival rate of 83% was developed. It was based on the experimental results obtained with explant pretreatment. Incubation time in liquid nitrogen did not affect the explants survival rate after thawing. After six months cryostorage of samples their genetic variability was analyzed. Six variable simple sequence repeat (SSR) loci were used to analyze genotype variability after the freezing-thawing procedure. The microsatellite analysis showed the genetic status identity of plants after cryopreservation and of the original genotypes. The presence of the recombinant gene in the transgenic lines after cryostorage were confirmed so as the interclonal variation in the growth rate under greenhouse conditions. The developed technique is recommended for long-term storage of various breeding and genetically modified lines of aspen plants, as it provides a high percentage of explants survival with no changes in genotype.

Association between Mode of Transportation and Survival in Adult Trauma Patients with Blunt Injuries: Matched Cohort Study between Police and Ground Ambulance Transport

2021 ◽  
pp. 1-9
Author(s):  
Fouad A. Sakr ◽  
Rana H. Bachir ◽  
Mazen J. El Sayed
Keyword(s):  
Cohort Study ◽  
Survival Rate ◽  
Blunt Trauma ◽  
Survival Rates ◽  
Trauma Patients ◽  
Matched Cohort ◽  
Matched Cohort Study ◽  
Blunt Injuries ◽  
Ground Ambulance ◽  
Mode Of Transportation

Abstract Introduction: Early police transport (PT) of penetrating trauma patients has the potential to improve survival rates for trauma patients. There are no well-established guidelines for the transport of blunt trauma patients by PT currently. Study Objective: This study examines the association between the survival rate of blunt trauma patients and the transport modality (police versus ground ambulance). Methods: A retrospective, matched cohort study was conducted using the National Trauma Data Bank (NTDB). All blunt trauma patients transported by police to trauma centers were identified and matched (one-to-four) to patients transported by ground Emergency Medical Services (EMS) for analysis. Descriptive analysis was carried out. This was followed by comparing all patients’ characteristics and their survival rates in terms of the mode of transportation. Results: Out of the 2,469 patients with blunt injuries, EMS transported 1,846 patients and police transported 623 patients. Most patients were 16-64 years of age (86.2%) with a male predominance (82.5%). Fall (38.4%) was the most common mechanism of injury with majority of injuries involving the head and neck body part (64.8%). Fractures were the most common nature of injury (62.1%). The overall survival rate of adult blunt trauma patients was similar for both methods of transportation (99.2%; P = 1.000). Conclusion: In this study, adult blunt trauma patients transported by police had similar outcomes to those transported by EMS. As such, PT in trauma should be encouraged and protocolized to improve resource utilization and outcomes further.

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