An assessment of the reliability of growth rings counts for age determination in the Hermann's Tortoise Testudo hermanni

2005 ◽  
Vol 26 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Albert Bertolero ◽  
Miguel Carretero ◽  
Gustavo Llorente
Keyword(s):  
Regression Analysis ◽  
Age Estimation ◽  
Sexual Maturity ◽  
Growth Ring ◽  
Linear Regression Analysis ◽  
Age Determination ◽  
Growth Rings ◽  
Direct Observations ◽  
Testudo Hermanni ◽  
Ne Spain

AbstractGrowth ring counts on the shell have been widely used for age estimation in Chelonians. However, as stated by Wilson et al. (2003), most studies have applied this method without assessing its reliability by proving that 1 : 1 ratio between number of rings and real age exists. In the present study, the reliability of this method is analysed for a population of Hermann's Tortoise, Testudo hermanni introduced in the Ebro Delta (NE Spain). Age estimations were obtained from direct observations of tortoises in the field in 2000 (n = 82) together with those from photographs of the same and other individuals of the population taken between 1991 and 2001 (n= 356). A second photograph was taken at one or more years after the first one for 101 individuals. Results of Model II linear regression analysis indicated that the method was reliable only for tortoises between 0 and 7 years old, whereas tended to underestimate age for those between 8 and 11 years. Since, sexual maturity in this population is attained around 8 years (mean for both sexes), ring counts are only reliable for juveniles and subadults. Finally, it is noteworthy that the results coming for photographs were equivalent to those coming from direct observations in the field.

Les marques de croissance des os et des écailles comme indicateur de l'âge chez Testudo hermanni et Testudo graeca (Reptilia, Chelonia, Testudinidae)

1979 ◽  
Vol 57 (8) ◽  
pp. 1649-1665 ◽  
Author(s):  
Jacques Castanet ◽  
Marc Cheylan
Keyword(s):  
Sexual Maturity ◽  
Bone Growth ◽  
Age Determination ◽  
Close Correlation ◽  
Long Bones ◽  
Histological Observation ◽  
Growth Rings ◽  
Testudo Graeca ◽  
Testudo Hermanni ◽  
Males And Females

This work shows the value of osseous growth marks for age determination in two terrestrial chelonia, Testudo hermanni and Testudo graeca. Careful histological observation of long bones proves that concentric rings show a yearly growth pattern; we have already described similar findings in amphibians, snakes, and lizards.We confirm these data first by the observation of some wild turtles of known age and of a close correlation between the number of bone rings and the number of rings on the cornified scutes. We also confirm in both species that scutes have a yearly growth rhythm and we conclude that bone growth marks provide a good criterion for age determination. Resorption destroys some juvenile rings; we propose a calculation to evaluate the number of resorbed lines to obtain the true individual age.In our turtles, scute growth rings allowed age determination until sexual maturity. With osseous growth marks, we were able to extend accurate ageing until the 20th year. We also established that sexual maturity occurs when animals are 12 or 13 years old in both species, with little difference between males and females.

Reproduction of the whiptail wallaby, Macropus parryi Bennett (Marsupialia : Macropodidae), in captivity with age estimation of the pouch-young

1998 ◽  
Vol 25 (6) ◽  
pp. 635 ◽  
Author(s):  
P. M. Johnson
Keyword(s):  
Age Estimation ◽  
Sexual Maturity ◽  
Post Partum ◽  
Age Determination ◽  
Oestrous Cycle ◽  
Gestation Period ◽  
Body Measurements ◽  
In Captivity ◽  
The Mean

Reproduction of the whiptail wallaby, Macropus parryi, was studied in captivity. The mean length of the oestrous cycle was 41.8 days while the mean length of the gestation period was 38.0 days. M. parryi bred throughout the year and post-partum oestrus was not recorded although mating did occur during the pouch life when the pouch-young was 118–168 days of age. The length of the pouch-life was 256–267 days and weaning occurred 104–215 days after emergence from the pouch. Sexual maturity for females occurred at 509–647 days of age. An age-determination table was produced and found useful for predicting age of pouch-young using body measurements.

LIGHT SHORTAGE AS A MODIFYING FACTOR FOR GROWTH DYNAMICS AND WOOD ANATOMY IN YOUNG DECIDUOUS TREES

IAWA Journal ◽  
2002 ◽  
Vol 23 (2) ◽  
pp. 121-141 ◽  
Author(s):  
Silke Hoffmann ◽  
Fritz H. Schweingruber
Keyword(s):  
Wood Anatomy ◽  
Growth Ring ◽  
Age Determination ◽  
Growth Dynamics ◽  
Deciduous Trees ◽  
Growth Rings ◽  
Term Survival ◽  
Additional Information ◽  
The Social

Suppressed trees growing under the canopy of mature forests exceed the number of tall, dominant individuals by far. This paper focuses on the wood structure of suppressed trees modified by light shortage. Secondly, the growth dynamics of suppressed deciduous trees within two sites was reconstructed by internal (tree rings) and external (bud scale scars) age determination. The social status of each specimen within the natural regeneration changes with time. Suppressed plants could once have held higher-ranking positions and individuals suffering from periods of suppression are able to recover after light conditions improve. This is an important process for the long-term survival strategy of shade tolerant tree species. Wood anatomy modified by suppression provides additional information on tree growth through the following properties: low percentage of pores in earlywood, changed distribution of pores, indistinct or absent growth ring boundaries, discontinuous growth rings. The low percentage of pores in earlywood may be a means of identifying light shortage in deciduous trees.

Dendrochronological Studies on Prosopis Flexuosa DC.

IAWA Journal ◽  
1989 ◽  
Vol 10 (2) ◽  
pp. 155-160 ◽  
Author(s):  
R. Villalba ◽  
J. A. Boninsegna
Keyword(s):  
Climatic Factors ◽  
Growth Ring ◽  
Age Determination ◽  
Cambial Activity ◽  
Vessel Diameter ◽  
Ecological Studies ◽  
Wood Production ◽  
Growth Rings ◽  
Undifferentiated Cells ◽  
Prosopis Flexuosa

Wood structure and seasonal variation of the cambial activity were investigated in Prosopis flexuosa DC. in order to enable the use of this species in dendrochronological and ecological studies requiring exact age determination. Cambial activity was determined by counting the number of undifferentiated cells in each radial file. Change in vessel diameter and a terminal parenchyma band, containing rhombic crystals, mark the annual growth layer. Even though the growth rings are not always clearly demarcated, one growth ring is generally formed each year. Prosopis flexuosa has an annual rhythm of wood production which coincides with the climatic rhythm. It is possible to cross-date disk samples of Prosopis species, and a first chronology has been established. Relationships between xylem production, phenology and climatic factors are discussed.

Prevalence and Predictors of Fruit Intake Among Community College Women in the Extended Opportunity Program and Services

2003 ◽  
Vol 1 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Steve E. Shive ◽  
Michelle R. Neyman
Keyword(s):  
Community College ◽  
Weight Loss ◽  
Regression Analysis ◽  
College Women ◽  
Linear Regression Analysis ◽  
Good Health ◽  
Fruit Intake ◽  
Attitudes And Behaviors ◽  
Eating Fruit ◽  
Opportunity Program

This study examined fruit intake among 276 female Extended Opportunity Program and Services (EOPS) community college students. Knowledge, attitudes, and behaviors associated with fruit intake were determined. The attitudes which are potential predictors of daily fruit intake were also examined. Analysis showed that 33% ate fewer than the minimum recommended two daily servings of fruit. Students reported that fruit gave them energy, taste and cost were not barriers to consumption and that it would not be difficult to increase daily fruit consumption. A linear regression analysis revealed that beliefs that eating fruit leads to good health, having a habit of eating fruit, feeling energy, and weight loss accounted for 30% of the variance in fruit intake.

ANALISIS PENGARUH INFLASI, KURS DAN IHSG TERHADAP RETURN REKSA DANA SAHAM PT NIKKO SECURITIES INDONESIA PERIODE 2014-2017

2019 ◽  
Vol 2 (2) ◽  
pp. 103
Author(s):  
Muhammad Rois Rois ◽  
Manarotul Fatati Fatati ◽  
Winda Ihda Magfiroh
Keyword(s):  
Regression Analysis ◽  
Exchange Rate ◽  
Linear Regression ◽  
Multiple Linear Regression ◽  
Stock Price ◽  
Price Index ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Equity Fund ◽  
Stock Price Index

This study aims to determine the effect of Inflation, Exchange Rate and Composite Stock Price Index (IHSG) to Return of PT Nikko Securities Indonesia Stock Fund period 2014-2017. The study used secondary data obtained through documentation in the form of PT Nikko Securities Indonesia Monthly Net Asset (NAB) report. Data analysis is used with quantitative analysis, multiple linear regression analysis using eviews 9. Population and sample in this research are PT Nikko Securities Indonesia. The result of multiple linear regression analysis was the coefficient of determination (R2) showed the result of 0.123819 or 12%. This means that the Inflation, Exchange Rate and Composite Stock Price Index (IHSG) variables can influence the return of PT Nikko Securities Indonesia's equity fund of 12% and 88% is influenced by other variables. Based on the result of the research, the variables of inflation and exchange rate have a negative and significant effect toward the return of PT Nikko Securities Indonesia's equity fund. While the variable of Composite Stock Price Index (IHSG) has a negative but not significant effect toward Return of Equity Fund of PT Nikko Securities Indonesia

Struktur Organisasi, Desain Kerja, Budaya Organisasi Dan Pengaruhnya Terhadap Produktivitas Karyawan Studi Kasus Pada PT. XX Di Jakarta

Liquidity ◽  
2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Yanti Budiasih
Keyword(s):  
Organizational Culture ◽  
Regression Analysis ◽  
Linear Regression ◽  
Organizational Structure ◽  
Research Method ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Job Design ◽  
Employee Productivity ◽  
Dominant Influence

The objectives of this study are to analyze changes in organizational structure, job design, organizational culture and its influence on employee productivity at PT. XX in Jakarta and to identify variables that have a dominant influence on the productivity of employees. The research method used is using multiple linear regression analysis. The results show that the all variables simultaneously and partially change the organizational structure, job design, and organizational culture has a significant impact on employee productivity at PT. XXin Jakarta.

The Contribution of Sexual Identity Towards the Students’ Perception of Lesbian, Gay, Bisexual, and Transgender

10.32698/0642 ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 120
Author(s):  
Wiwi Delfita ◽  
Neviyarni S. ◽  
Riska Ahmad
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Sexual Identity ◽  
Student Perceptions ◽  
Undergraduate Students ◽  
Linear Regression Analysis ◽  
Sampling Technique ◽  
Simple Linear Regression ◽  
Simple Linear Regression Analysis ◽  
Bisexual And Transgender

Some students perceive lesbian, gay, bisexual, and transgender (LGBT) positively, even though LGBT is a sexual deviation that is not appropriate with values and norms. There are several factors that influence an individual's perception of LGBT, including sexual identity. This study aims at looking at the contribution of sexual identity to student perceptions about LGBT. This research used a quantitative approach with a descriptive method and a simple linear regression analysis. The sample of this research was 385 taken from 15.752 undergraduate students of Universitas Negeri Padang which the sample was drawn by using the Slovin formula and continued with a Proportional Random Sampling technique. The instrument used was the Guttman model's sexual identity scale and the scale of students' perceptions of the LGBT Likert model. After analyzing the data with the descriptive technique and the simple linear regression analysis, the results showed that sexual identity significantly contributed to the students' perceptions of LGBT. This research has implications as a basis for counselors to help students avoid sexual identity mismatches and prevent the emergence of positive perceptions of LGBT.

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