scholarly journals Relatively low tooth replacement rate in a sauropod dinosaur from the Early Cretaceous Ruyang Basin of central China

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12361
Author(s):  
Huali Chang ◽  
Hai-Lu You ◽  
Li Xu ◽  
Waisum Ma ◽  
Diansong Gao ◽  
...  
Keyword(s):  
Anatomical Study ◽  
Central China ◽  
Tooth Replacement ◽  
Replacement Rate ◽  
Tooth Formation ◽  
Single Crown ◽  
Feeding Mechanics ◽  
Data Points ◽  
Few Data ◽  
Rostral Portion

Tooth replacement rate is an important feature related to feeding mechanics and food choices for dinosaurs. However, only a few data points are available for sauropod dinosaurs, partially due to rarity of relevant fossil material. Four somphospondylan sauropod species have been recovered from the Lower Cretaceous Aptian–Albian Haoling Formation in the Ruyang Basin, Henan Province of central China, but no cranial material has been reported except for a single crown. Here we report the discovery of the rostral portion of a left dentary with replacement teeth in its first five alveoli. Comparative anatomical study shows the partial dentary can be assigned to a member of early diverging somphospondylans. The non-destructive tooth length-based approach to estimating tooth formation time and replacement rate is adopted here. The estimated tooth replacement rate is 76 days, faster than that of Brachiosaurus (83 days) and much lower than typical late diverging lithostrotian titanosaurians (20 days). Thus, this discovery adds an intermediate tooth replacement rate in the evolution of titanosauriform sauropods and supports the idea that evolution of tooth replacement rate is clade-specific. This discovery also provides more information to understand the Ruyang sauropod assemblage, which includes one of the most giant dinosaurs to have walked our Earth (Ruyangosaurus giganteus).

scholarly journals Sampling impacts the assessment of tooth growth and replacement rates in archosaurs: implications for paleontological studies

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9918
Author(s):  
Jens C.D. Kosch ◽  
Lindsay E. Zanno
Keyword(s):  
Dietary Habits ◽  
Small Sample ◽  
Formation Time ◽  
Alligator Mississippiensis ◽  
Central Axis ◽  
Tooth Replacement ◽  
Replacement Rate ◽  
Tooth Formation ◽  
Dental Tissues ◽  
Sampling Protocols

Dietary habits in extinct species cannot be directly observed; thus, in the absence of extraordinary evidence, they must be reconstructed with a combination of morphological proxies. Such proxies often include information on dental organization and function such as tooth formation time and tooth replacement rate. In extinct organisms, tooth formation times and tooth replacement rate are calculated, in part via extrapolation of the space between incremental lines in dental tissues representing daily growth (von Ebner Line Increment Width; VEIW). However, to date, little work has been conducted testing assumptions about the primary data underpinning these calculations, specifically, the potential impact of differential sampling and data extrapolation protocols. To address this, we tested a variety of intradental, intramandibular, and ontogentic sampling effects on calculations of mean VEIW, tooth formation times, and replacement rates using histological sections and CT reconstructions of a growth series of three specimens of the extant archosaurian Alligator mississippiensis. We find transect position within the tooth and transect orientation with respect to von Ebner lines to have the greatest impact on calculations of mean VEIW—a maximum number of VEIW measurements should be made as near to the central axis (CA) as possible. Measuring in regions away from the central axis can reduce mean VEIW by up to 36%, causing inflated calculations of tooth formation time. We find little demonstrable impact to calculations of mean VEIW from the practice of subsampling along a transect, or from using mean VEIW derived from one portion of the dentition to extrapolate for other regions of the dentition. Subsampling along transects contributes only minor variations in mean VEIW (<12%) that are dwarfed by the standard deviation (SD). Moreover, variation in VEIW with distance from the pulp cavity likely reflects idiosyncratic patterns related to life history, which are difficult to control for; however, we recommend increasing the number of VEIW measured to minimize this effect. Our data reveal only a weak correlation between mean VEIW and body length, suggesting minimal ontogenetic impacts. Finally, we provide a relative SD of mean VEIW for Alligator of 29.94%, which can be used by researchers to create data-driven error bars for tooth formation times and replacement rates in fossil taxa with small sample sizes. We caution that small differences in mean VEIW calculations resulting from non-standardized sampling protocols, especially in a comparative context, will produce inflated error in tooth formation time estimations that intensify with crown height. The same holds true for applications of our relative SD to calculations of tooth formation time in extinct taxa, which produce highly variable maximum and minimum estimates in large-toothed taxa (e.g., 718–1,331 days in Tyrannosaurus).

scholarly journals Faking Signals to Fool Deep Neural Networks in AMC via Few Data Points

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Hongbin Ma ◽  
Shuyuan Yang ◽  
Guangjun He ◽  
Ruowu Wu ◽  
Xiaojun Hao ◽  
...  
Keyword(s):  
Neural Networks ◽  
Deep Neural Networks ◽  
Data Points ◽  
Few Data

Wheat Prices and Trade in the Early Roman Empire

2012 ◽  
Author(s):  
Peter Temin
Keyword(s):  
Roman Empire ◽  
Roman Republic ◽  
Small Data ◽  
Data Sets ◽  
Data Points ◽  
Small Data Sets ◽  
Few Data ◽  
Late Roman

This chapter discusses how there is little of what economists call data on markets in Roman times, despite lots of information about prices and transactions. Data, as economists consider it, consist of a set of uniform prices that can be compared with each other. According to scholars, extensive markets existed in the late Roman Republic and early Roman Empire. Even though there is a lack of data, there are enough observations for the price of wheat, the most extensively traded commodity, to perform a test. The problem is that there is only a little bit of data by modern standards. Consequently, the chapter explains why statistics are useful in interpreting small data sets and how one deals with various problems that arise when there are only a few data points.

A New Nonlinear Least Square Algorithm for Voigt Spectral Lines

1980 ◽  
Vol 34 (3) ◽  
pp. 351-360 ◽  
Author(s):  
R. J. Noll ◽  
A. Pires
Keyword(s):  
Least Square ◽  
Spectral Lines ◽  
Single Line ◽  
Second Derivatives ◽  
Fitting Algorithm ◽  
Starting Conditions ◽  
Data Points ◽  
Lorentz Line ◽  
Few Data ◽  
Raphson Method

In this paper a new fitting algorithm which works with Voigt functions is discussed. The fitting algorithm used is an extension of the rapidly convergent gradient method of Fletcher and Powell, who claim faster convergence than the Newton-Raphson method which has been used by Chang and Shaw for fitting Lorentz line widths. The Fletcher and Powell algorithm involves the effects of second derivatives although second derivatives are not explicitly calculated. In our algorithm, first and second derivatives are computed not numerically, but analytically via a modification to Drayson's Voigt function subroutine. This algorithm provides rapid convergence even when there are few data points. Profiles have been fitted with as few as five data points. Our typical line fits involve 40 points. The run time of the algorithm has been compared with the shrinking cube algorithm of Hillman and found to be at least 10 times faster under identical starting conditions. Sample single line and single line plus background are shown illustrating the speed and efficiency of the new algorithm, as well as the importance of good zero-order estimates to start the iterations.

scholarly journals Lower Permian brachiopods from Oman: their potential as climatic proxies

2007 ◽  
Vol 98 (3-4) ◽  
pp. 327-344 ◽  
Author(s):  
L. Angiolini ◽  
D. P. F. Darbyshire ◽  
M. H. Stephenson ◽  
M. J. Leng ◽  
T. S. Brewer ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Isotopic Analysis ◽  
Lower Permian ◽  
Published Data ◽  
Sr Isotope ◽  
Marine Sedimentation ◽  
Ice Accumulation ◽  
Secondary Layer ◽  
Data Points ◽  
Few Data

ABSTRACTThe Lower Permian of the Haushi basin, Interior Oman (Al Khlata Formation to Saiwan Formation/lower Gharif member) records climate change from glaciation, through marine sedimentation in the Haushi sea, to subtropical desert. To investigate the palaeoclimatic evolution of the Haushi Sea we used O, C, and Sr isotopes from 31 brachiopod shells of eight species collected bed by bed within the type-section of the Saiwan Formation. We assessed diagenesis by scanning electron microscopy of ultrastructure, cathodoluminescence, and geochemistry, and rejected fifteen shells not meeting specific preservation criteria. Spiriferids and spiriferinids show better preservation of the fibrous secondary layer than do orthotetids and productids and are therefore more suitable for isotopic analysis. δ18O of −3·7 to −3·1℅ from brachiopods at the base of the Saiwan Formation are probably related to glacial meltwater. Above this, an increase in δ18O may indicate ice accumulation elsewhere in Gondwana or more probably that the Haushi sea was an evaporating embayment of the Neotethys Ocean. δ13C varies little and is within the range of published data: its trend towards heavier values is consistent with increasing aridity and oligotrophy. Saiwan Sr isotope signatures are less radiogenic than those of the Sakmarian LOWESS seawater curve, which is based on extrapolation between few data points. In the scenario of evaporation in a restricted Haushi basin, the variation in Sr isotope composition may reflect a fluvial component.

A NOVEL VALIDITY INDEX FOR THE SUBTRACTIVE CLUSTERING ALGORITHM

2011 ◽  
Vol 25 (04) ◽  
pp. 547-563 ◽  
Author(s):  
HORNG-LIN SHIEH ◽  
CHENG-CHIEN KUO
Keyword(s):  
Clustering Algorithm ◽  
Optimal Number ◽  
Subtractive Clustering ◽  
Cluster Validity ◽  
Cluster Validity Index ◽  
Validity Index ◽  
Simple Method ◽  
Data Points ◽  
Few Data ◽  
Performance Results

This paper proposes a new validity index for the subtractive clustering (SC) algorithm. The subtractive clustering algorithm proposed by Chiu is an effective and simple method for identifying the cluster centers of sampling data based on the concept of a density function. The SC algorithm continually produces the cluster centers until the final potential compared with the original is less than a predefined threshold. The procedure is terminated when there are only a few data points around the most recent cluster. The choice of the threshold is an important factor affecting the clustering results: if it is too large, then too few data points will be accepted as cluster centers; if it is too small, then too many cluster centers will be generated. In this paper, a modified SC algorithm for data clustering based on a cluster validity index is proposed to obtain the optimal number of clusters. Six examples show that the proposed index achieves better performance results than other cluster validities do.

scholarly journals Estimating parameter values of a socio-hydrological flood model

2018 ◽  
Vol 379 ◽  
pp. 193-198
Author(s):  
Marlies Holkje Barendrecht ◽  
Alberto Viglione ◽  
Heidi Kreibich ◽  
Sergiy Vorogushyn ◽  
Bruno Merz ◽  
...  
Keyword(s):  
Time Series ◽  
Case Studies ◽  
Hydrological Model ◽  
Promising Tool ◽  
Flood Model ◽  
Modelling Studies ◽  
Data Points ◽  
Few Data ◽  
Parameter Values

Abstract. Socio-hydrological modelling studies that have been published so far show that dynamic coupled human-flood models are a promising tool to represent the phenomena and the feedbacks in human-flood systems. So far these models are mostly generic and have not been developed and calibrated to represent specific case studies. We believe that applying and calibrating these type of models to real world case studies can help us to further develop our understanding about the phenomena that occur in these systems. In this paper we propose a method to estimate the parameter values of a socio-hydrological model and we test it by applying it to an artificial case study. We postulate a model that describes the feedbacks between floods, awareness and preparedness. After simulating hypothetical time series with a given combination of parameters, we sample few data points for our variables and try to estimate the parameters given these data points using Bayesian Inference. The results show that, if we are able to collect data for our case study, we would, in theory, be able to estimate the parameter values for our socio-hydrological flood model.

Parameter Estimation in Models of Cell Survival Using Scaled Time

2013 ◽  
Author(s):  
Neil T. Wright
Keyword(s):  
Cell Survival ◽  
Treatment Time ◽  
Treatment Temperature ◽  
Separate Experiment ◽  
Small Data ◽  
Data Sets ◽  
Data Points ◽  
Isothermal Analysis ◽  
Time Required ◽  
Few Data

Many individual samples are needed to measure cell survival following heating at multiple temperatures and multiple heating durations. For example, if eight time points are considered for each of seven treatment temperatures with three replicates at each condition, then 168 separate samples are needed. In addition, physical considerations may limit the number of points that can be measured, especially as treatment temperature increases and the heating duration decreases. For a reasonable sample size, there may be a limit to the treatment temperature as the time required to heat the culture to the target temperature becomes comparable to the treatment time. Then, using an isothermal analysis of the data introduces error and the temperature must be considered time varying, requiring estimates of the very parameters being sought. Conversely, for long treatment times, it may be difficult to insure that the temperature remains constant and that the temperature is the only modified experimental condition in the culture medium. These challenges typically lead to relatively small data sets. Furthermore, treating each temperature as a separate experiment leads to challenging statistical analysis of the data, as the few data points lead to difficulty in finding the confidence intervals of the parameters in a given model.

scholarly journals An Analysis for the Applicability of Monin–Obukhov Similarity Theory in Stable Conditions

2012 ◽  
Vol 69 (6) ◽  
pp. 1910-1915 ◽  
Author(s):  
Pramod Kumar ◽  
Maithili Sharan
Keyword(s):  
Similarity Theory ◽  
Ground Surface ◽  
Surface Fluxes ◽  
Stability Parameters ◽  
Surface Exchange ◽  
Obukhov Length ◽  
Stable Conditions ◽  
Data Points ◽  
The Stability ◽  
Few Data

Abstract An analysis in a plane of the stability parameters ζ = z/L (where z is a height above the ground surface and L is the Obukhov length) and bulk Richardson number RiB is proposed to examine the applicability of Monin–Obukhov similarity (MOS) theory in stable conditions. In this analysis, the data available from two different experimental datasets [(i) Cooperative Atmosphere–Surface Exchange Study-1999 (CASES-99) and (ii) Cardington] are divided into four quadrants. An unexpected behavior of decreasing ζ with increasing RiB was observed with both datasets in quadrant II characterized by ζ &lt; 1 and RiB &gt; 0.2 and in quadrant IV with ζ &gt; 1 and RiB &lt; 0.2. This is in contrast to a commonly expected monotonically increasing behavior between ζ and RiB. It is shown that the MOS theory is consistent for computing the surface fluxes corresponding to the data points lying in quadrants I (with ζ &gt; 1 and RiB &gt; 0.2) and III (with ζ &lt; 1 and RiB &lt; 0.2), whereas it may not be applicable for the points in quadrants II and IV. Thus, a breakdown of the relationship between observed ζ and RiB with growing stability in these quadrants may limit the applicability of MOS theory in stable conditions. Since quadrant IV has very few data points, the applicability of MOS theory needs to be substantiated further with the availability of sufficient data points in this regime.

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