Growth dynamics of freshwater crocodiles (Crocodylus johnstoni) in the Lynd River, Queensland

2006 ◽  
Vol 54 (6) ◽  
pp. 409 ◽  
Author(s):  
Anton D. Tucker ◽  
Colin J. Limpus ◽  
Keith R. McDonald ◽  
Hamish I. McCallum
Keyword(s):  
Growth Models ◽  
Growth Dynamics ◽  
Interval Data ◽  
Age And Growth ◽  
Data Sets ◽  
Size Dimorphism ◽  
Crocodylus Johnstoni ◽  
Trade Offs ◽  
Capture Recapture ◽  
Australian Freshwater

We analysed growth models for a population of Australian freshwater crocodiles (Crocodylus johnstoni). Competing growth models were tested with two data sets: individuals of known-age, and growth interval data from capture-recapture records. A von Bertalanffy function provided the best empirical fit of several growth models. The estimated asymptotic lengths (snout–vent length of males = 125.3 cm; females = 97.4 cm) agreed well with average lengths of the ten largest males and females in the population. Sexual size dimorphism in this species resulted from a combination of smaller mean length at maturity for females and a subsequent decline in female growth rate. Size dimorphism may result from individual trade-offs in age v. length at maturity as a consequence of sexual selection.

Age and growth dynamics of spiny dogfish, Squalus acanthias, in the Adriatic Sea (Eastern Mediterranean Sea)

2016 ◽  
Vol 67 (3) ◽  
pp. 357 ◽  
Author(s):  
Romana Gračan ◽  
Scott A. Heppell ◽  
Gordana Lacković ◽  
Bojan Lazar
Keyword(s):  
Adriatic Sea ◽  
Growth Models ◽  
Eastern Mediterranean ◽  
Growth Dynamics ◽  
Fishing Effort ◽  
Age And Growth ◽  
Percentage Error ◽  
Parameter Estimates ◽  
Spiny Dogfish ◽  
Average Percentage

This research provides the first information on age and growth estimates for the endangered Mediterranean subpopulation of spiny dogfish, a commercially exploited shark, highly sensitive to overexploitation. We collected samples from 206 specimens caught by commercial bottom trawls in the Adriatic Sea, and utilising three ageing protocols achieved good agreement between the readings (average percentage error=1.65%). Four growth models were fitted to length-at-age and weight-at-age data, for each sex separately. The Gompertz growth model produced the statistically best fit resulting in the following parameters: k values for males and females were 0.09 and 0.04 year–1, size-at-birth ranged from 22.9 to 24.1-cm total length, with a theoretical asymptotic length of 103.3cm for males and 173.3cm for females. The age at 50% maturity was 10.5 years for males and 20.1 years for females. The maximum age was estimated at 23 years for males and 36 years for females, with natural mortality estimates of 0.12 for males and 0.07 for females. As a result of reported demographic parameter estimates, high fishing effort and particularly low resilience of the species to exploitation, it is important to produce proper species-specific management strategy for the spiny dogfish in the region.

scholarly journals Stochastic Models for Revealing the Dynamics of the Growth of Small Tumor Populations

2019 ◽  
Author(s):  
Kaitlyn E. Johnson ◽  
Amy Brock
Keyword(s):  
Growth Models ◽  
Growth Dynamics ◽  
Large Data ◽  
Population Variation ◽  
Large Data Sets ◽  
Death Process ◽  
Data Sets ◽  
Modeling Framework ◽  
Small Tumor ◽  
Constant Rate

AbstractThe widely accepted model of tumor growth assumes tumors grow exponentially at a constant rate during early tumorigenesis when populations are small. The possibility that tumors might exhibit altered slower growth dynamics or even net cell death below a critical tumor size has yet to be fully explored. Deterministic growth models are capable of describing larger populations because population variation becomes small compared with the average, but when the population being modeled is small, the inherent stochasticity of the birth and death process produces significant variation. Recent advances in high throughput data collection allow for precise and sufficiently large data sets needed to capture this variation. Therefore, we present a stochastic modeling framework to describe and test the potential for altered growth dynamics at small tumor populations.

scholarly journals Fundamental resource trade-offs for encoded distributed optimization

2020 ◽  
Author(s):  
A Salman Avestimehr ◽  
Seyed Mohammadreza Mousavi Kalan ◽  
Mahdi Soltanolkotabi
Keyword(s):  
Computational Time ◽  
Massive Data ◽  
Data Sets ◽  
Massive Data Sets ◽  
Computational Framework ◽  
Data Set ◽  
Trade Offs ◽  
Major Bottleneck ◽  
Computing Environments ◽  
Analyze Data

Abstract Dealing with the shear size and complexity of today’s massive data sets requires computational platforms that can analyze data in a parallelized and distributed fashion. A major bottleneck that arises in such modern distributed computing environments is that some of the worker nodes may run slow. These nodes a.k.a. stragglers can significantly slow down computation as the slowest node may dictate the overall computational time. A recent computational framework, called encoded optimization, creates redundancy in the data to mitigate the effect of stragglers. In this paper, we develop novel mathematical understanding for this framework demonstrating its effectiveness in much broader settings than was previously understood. We also analyze the convergence behavior of iterative encoded optimization algorithms, allowing us to characterize fundamental trade-offs between convergence rate, size of data set, accuracy, computational load (or data redundancy) and straggler toleration in this framework.

scholarly journals Age and growth of franciscana dolphins, Pontoporia blainvillei (Cetacea: Pontoporiidae) incidentally caught off southern Brazil and northern Argentina

2010 ◽  
Vol 90 (8) ◽  
pp. 1493-1500 ◽  
Author(s):  
Silvina Botta ◽  
Eduardo R. Secchi ◽  
Mônica M.C. Muelbert ◽  
Daniel Danilewicz ◽  
Maria Fernanda Negri ◽  
...  
Keyword(s):  
Growth Models ◽  
Growth Curves ◽  
Small Sample ◽  
Age And Growth ◽  
Buenos Aires Province ◽  
Von Bertalanffy ◽  
Southern Brazil ◽  
Data Set ◽  
Males And Females ◽  
Pontoporia Blainvillei

Age and length data of 291 franciscana dolphins (Pontoporia blainvillei) incidentally captured on the coast of Rio Grande do Sul State (RS), southern Brazil, were used to fit growth curves using Gompertz and Von Bertalanffy growth models. A small sample of franciscanas (N = 35) from Buenos Aires Province (BA), Argentina, were used to see if there are apparent growth differences between the populations. Male and female franciscana samples from both areas were primarily (78–85%) <4 years of age. The Von Bertalanffy growth model with a data set that excluded animals <1 year of age provided the best fit to data. Based on this model, dolphins from the RS population reached asymptotic length at 136.0 cm and 158.4 cm, for males and females, respectively. No remarkable differences were observed in the growth trajectories of males and females between the RS and BA populations.

Absence of Trade-Offs Between Sexual Size Dimorphism and Early Male Emergence in a Butterfly

Ecology ◽  
1993 ◽  
Vol 74 (5) ◽  
pp. 1414-1427 ◽  
Author(s):  
Soren Nylin ◽  
Christer Wiklund ◽  
Per-Olof Wickman ◽  
Enrique Garcia-Barros
Keyword(s):  
Sexual Size Dimorphism ◽  
Size Dimorphism ◽  
Trade Offs

Age and growth of the Patagonian lizard Phymaturus patagonicus

2006 ◽  
Vol 27 (3) ◽  
pp. 385-392 ◽  
Author(s):  
Carla Piantoni ◽  
Victor Cussac ◽  
Nora Ibargüengoytía
Keyword(s):  
Body Length ◽  
Cross Sections ◽  
Growth Dynamics ◽  
Strong Relationship ◽  
Age And Growth ◽  
Adult Males ◽  
Patagonian Steppe ◽  
The North ◽  
Sigmoidal Curve ◽  
Reproductive Cycles

AbstractThe growth dynamics of Phymaturus patagonicus, a diurnal, herbivorous and viviparous lizard from the Argentinean Patagonian steppe, was studied using eight juveniles (two born in the laboratory), 11 adult females and eight adult males. Histological cross sections of femoral bones were analysed to determine if individuals show osseous growth marks and if these marks provide useful age estimates. Individual ages were assessed after estimating the reabsorbed rings in relation to snout-vent length. There was a strong relationship between body length and estimated age, modelled by a sigmoidal curve. Sexual maturity was found to be reached at seven years in females and nine in males and the maximum life span was estimated to be 16 years. No difference in body length was observed between the same-age females and males. We postulate that severe environments such as the north Patagonian steppe play a significant role in the selection of not only modes of reproduction but also delayed maturity and prolonged reproductive cycles, a combination that results in low fecundity.

Dynamic Measurement Modeling: Using Nonlinear Growth Models to Estimate Student Learning Capacity

2017 ◽  
Vol 46 (6) ◽  
pp. 284-292 ◽  
Author(s):  
Denis G. Dumas ◽  
Daniel M. McNeish
Keyword(s):  
Multiple Testing ◽  
Large Scale ◽  
Growth Models ◽  
Dynamic Assessment ◽  
The United States ◽  
Dynamic Measurement ◽  
Data Sets ◽  
Data Systems ◽  
Longitudinal Assessment ◽  
Assessment Practice

Single-timepoint educational measurement practices are capable of assessing student ability at the time of testing but are not designed to be informative of student capacity for developing in any particular academic domain, despite commonly being used in such a manner. For this reason, such measurement practice systematically underestimates the potential of students from nondominant socioeconomic or ethnic groups, who may not have had adequate opportunity to develop various academic skills but can nonetheless do so in the future. One long-standing approach to the partial rectification of this issue is dynamic assessment (DA), a technique that features multiple testing occasions integrated with learning opportunities. However, DA is extremely resource intensive to incorporate into educational assessment practice and cannot be applied to extant large-scale data sets. In this article, the authors describe a recently developed statistical technique, dynamic measurement modeling (DMM), which is capable of estimating quantities associated with DA—including student capacity for learning a particular skill—from existing large-scale longitudinal assessment data, allowing the core concepts of DA to be scaled up for use with secondary data sets such as those collected by Statewide Longitudinal Data Systems in the United States. The authors show that by considering several assessments over time, student capacity can be reliably estimated, and these capacity estimates are much less affected by student race/ethnicity, gender, and socioeconomic status than are single-timepoint assessment scores, thereby improving the consequential validity of measurement.

scholarly journals Competitive exclusion and metabolic dependency among microorganisms structure the cellulose economy of agricultural soil

2020 ◽  
Author(s):  
Roland C Wilhelm ◽  
Charles Pepe-Ranney ◽  
Pamela Weisenhorn ◽  
Mary Lipton ◽  
Daniel H. Buckley
Keyword(s):  
Microbial Growth ◽  
Competitive Exclusion ◽  
Antibiotic Production ◽  
Growth Dynamics ◽  
Soil Disturbance ◽  
Gliding Motility ◽  
Cellulolytic Microorganisms ◽  
Trade Offs ◽  
Self Sufficiency ◽  
Attachment Structures

Abstract Many cellulolytic microorganisms degrade cellulose through extracellular processes that yield free intermediates which promote interactions with non-cellulolytic organisms. We hypothesize that these interactions determine the ecological and physiological traits that govern the fate of cellulosic carbon (C) in soil. We evaluated the genomic potential of soil microorganisms that access C from 13 C-labeled cellulose. We used metagenomic-SIP and metaproteomics to evaluate whether cellulolytic and non-cellulolytic microbes that access 13 C from cellulose encode traits indicative of metabolic dependency or competitive exclusion. The most highly 13 C-enriched taxa were cellulolytic Cellvibrio ( Gammaproteobacteria ) and Chaetomium ( Ascomycota ), which exhibited a strategy of self-sufficiency (prototrophy), rapid growth, and competitive exclusion via antibiotic production. These ruderal taxa were common indicators of soil disturbance in agroecosystems, such as tillage and fertilization. Auxotrophy was more prevalent in cellulolytic Actinobacteria than in cellulolytic Proteobacteria , demonstrating differences in dependency among cellulose degraders. Non-cellulolytic taxa that accessed 13 C from cellulose ( Planctomycetales , Verrucomicrobia and Vampirovibrionales ) were highly dependent, as indicated by patterns of auxotrophy and 13 C-labeling (i.e. partial labelling or labeling at later-stages). Major 13 C-labeled cellulolytic microbes ( e.g. Sorangium, Actinomycetales, Rhizobiales and Caulobacteraceae ) possessed adaptations for surface colonization ( e.g. gliding motility, hyphae, attachment structures) signifying the importance of surface ecology in decomposition. These results suggest that access to cellulose was accompanied by ecological trade-offs characterized by differing degrees of metabolic dependency and competitive exclusion. These trade-offs likely influence microbial growth dynamics on particulate organic carbon and reveal that the fate of carbon is governed by a complex economy within the microbial community.

scholarly journals A skeletochronological estimate of age and growth in a large riparian frog from Madagascar (Anura, Mantellidae, Mantidactylus)

Herpetozoa ◽  
2019 ◽  
Vol 32 ◽  
pp. 39-44 ◽  
Author(s):  
Fabio M. Guarino ◽  
Angelica Crottini ◽  
Marcello Mezzasalma ◽  
Jasmin E. Randrianirina ◽  
Franco Andreone
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Sexual Size Dimorphism ◽  
The Body ◽  
Age And Growth ◽  
Growth Trajectories ◽  
Growth Coefficient ◽  
Size Dimorphism ◽  
Adult Females ◽  
Similar Growth

We characterized the body size (as snout-vent length), age, sexual size dimorphism, and growth rate in a population of one of the larger riparian frog from Madagascar (Mantidactylusgrandidieri) from a rainforest patch close to Vevembe, SE Madagascar. We identified a significant female-biased sexual size dimorphism. Age was estimated using phalangeal skeletochronology and was significantly higher in females than in males. Modal age class turned out to be 4 years in both sexes but a large percentage of adult females (75%) fell in the 5–6 years-old classes, while no male exceeded 4 years. We here report M.grandidieri as a medium-long-lived anuran species. Von Bertalanffy’s model showed similar growth trajectories between the sexes although the growth coefficient in females (k = 0.335) was slightly but not significantly higher than in males (k = 0.329).

Hedonic Price Analysis in Food Markets

2011 ◽  
pp. 151-180 ◽  
Author(s):  
Marco Costanigro ◽  
Jill J. Mccluskey
Keyword(s):  
Large Data ◽  
Data Sets ◽  
Hedonic Price ◽  
Long Term Effects ◽  
Food Markets ◽  
Regulatory Policies ◽  
Hedonic Price Analysis ◽  
Trade Offs ◽  
Price Relationship ◽  
Implicit Prices

This article presents the basic theory of hedonic modeling, its empirical application and relevance, and the principal limitations and challenges. Agricultural economists have long utilized the hedonic price relationship, and the hedonic price technique has been utilized to estimate the implicit prices of attributes for numerous food products. It provides a framework of the hedonic models that can be used to quantify the long-term effects of exogenous shocks on quality, or implementation of regulatory policies. This article discusses the whole armamentarium of econometric models and methods familiar to applied economists, including parametric, semi-parametric, and non-parametric approaches. The objective is to describe briefly each econometric model within the hedonic context and provide an understanding of the implications and trade-offs inherent to the choice of each alternative. This is a fruitful area of research with increased customization of products and the increasing availability of large data sets.

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