scholarly journals How many ontogenetic points are needed to accurately describe the ontogeny of a cephalopod conch? A case study of the modern nautilid Nautilus pompilius

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8849
Author(s):  
Amane Tajika ◽  
Christian Klug
Keyword(s):  
Morphological Analysis ◽  
Growth Trajectories ◽  
Nautilus Pompilius ◽  
Ontogenetic Trajectories ◽  
Tomographic Data ◽  
Growth Changes ◽  
Growth Change ◽  
External Stimuli ◽  
Ideal Group

Recent advancements in tomographic techniques allow for detailed morphological analysis of various organisms, which has proved difficult in the past. However, the time and cost required for the post-processing of highly resolved tomographic data are considerable. Cephalopods are an ideal group to study ontogeny using tomography as the entire life history is preserved within a conch. Although an increasing number of studies apply tomography to cephalopod conchs, the number of conch measurements needed to adequately characterize ontogeny remains unknown. Therefore, the effect of different ontogenetic sampling densities on the accuracy of the resultant growth trajectories needs to be investigated. Here, we reconstruct ontogenetic trajectories of a single conch of Nautilus pompilius using different numbers of ontogenetic points to assess the resulting accuracies. To this end, conch parameters were measured every 10°, 30°, 45°, 90°, and 180°. Results reveal that the overall patterns of reconstructed growth trajectories are nearly identical. Relatively large errors appear to occur where growth changes occur, such as the points of hatching and the onset of morphogenetic countdown before the attainment of maturity. In addition, a previously undocumented growth change before hatching was detected when measurements were taken every 10°, 30°, and 45°, though this growth change was obscured when fewer measurements were used (90° and 180°). The lower number of measurements also masks the subtle fluctuating patterns of conch parameters in middle ontogeny. We conclude that the measurements of a conch every 30° and 45° permit a reasonably precise description of conch ontogeny in nautilids. Since ammonoids were likely more responsive to external stimuli than to nautilids, a much denser sampling may be required for ammonoids.

Skeleton formation in the Branchiosauridae: a case study in comparing ontogenetic trajectories

10.1671/1950 ◽  
2004 ◽  
Vol 24 (2) ◽  
pp. 309-319 ◽  
Author(s):  
Rainer R. Schoch
Keyword(s):  
Ontogenetic Trajectories ◽  
Skeleton Formation

Ontogeny in the steinmanellines (Bivalvia: Trigoniida): an intra- and interspecific appraisal using the Early Cretaceous faunas from the Neuquén Basin as a case study

Paleobiology ◽  
2021 ◽  
pp. 1-23
Author(s):  
Pablo S. Milla Carmona ◽  
Dario G. Lazo ◽  
Ignacio M. Soto
Keyword(s):  
Trajectory Analysis ◽  
Sedentary Lifestyle ◽  
Shape Change ◽  
Shell Shape ◽  
Shape Variation ◽  
Ontogenetic Changes ◽  
Ontogenetic Trajectories ◽  
Higher Genus ◽  
Gradual Decay

Abstract Despite the paleontological relevance and paleobiological interest of trigoniid bivalves, our knowledge of their ontogeny—an aspect of crucial evolutionary importance—remains limited. Here, we assess the intra- and interspecific ontogenetic variations exhibited by the genus Steinmanella Crickmay (Myophorellidae: Steinmanellinae) during the early Valanginian–late Hauterivian of Argentina and explore some of their implications. The (ontogenetic) allometric trajectories of seven species recognized for this interval were estimated from longitudinal data using 3D geometric morphometrics, segmented regressions, and model selection tools, and then compared using trajectory analysis and allometric spaces. Our results show that within-species shell shape variation describes biphasic ontogenetic trajectories, decoupled from ontogenetic changes shown by sculpture, with a gradual decay in magnitude as ontogeny progresses. The modes of change characterizing each phase (crescentic growth and anteroposterior elongation, respectively) are conserved across species, thus representing a feature of Steinmanella ontogeny; its evolutionary origin is inferred to be a consequence of the rate modification and allometric repatterning of the ancestral ontogeny. Among species, trajectories are more variable during early ontogenetic stages, becoming increasingly conservative at later stages. Trajectories’ general orientation allows recognition of two stratigraphically consecutive groups of species, hinting at a potentially higher genus-level diversity in the studied interval. In terms of functional morphology, juveniles had a morphology more suited for active burrowing than adults, whose features are associated with a sedentary lifestyle. The characteristic disparity of trigoniids could be related to the existence of an ontogenetic period of greater shell malleability betrayed by the presence of crescentic shape change.

Revaluation of Ksar El-Haouita in Laghouat, Algeria

2021 ◽  
Author(s):  
Fatiha Imane Mahcar ◽  
Belkacem Takhi
Keyword(s):  
Morphological Analysis ◽  
Construction Materials ◽  
Architectural Heritage ◽  
Theoretical Underpinning ◽  
Great Resistance ◽  
Basic Principles ◽  
Construction Techniques ◽  
Materials Used ◽  
Local Materials

Algeria has a rich urban and architectural heritage, which presents regional specificities. Once the ksour was a symbol of balance and perfect harmony with its environment, unfortunately today they no longer reflect their former function. The Ksourian architecture, including that of Laghouat is a prestigious heritage of high value; it is the testimony of genius knowledge and the capacity of their occupants to adapt to the difficult environment. The housing is considered the essential core of this architecture it represents the entire composition of the ksar, its design is inspired by the immediate environment and respects ancestral social values. It is characterized by a simple architecture and simple construction techniques which are based on the construction in load-bearing walls, the construction materials used are local materials of great resistance and less expensive. This study addresses the theme revaluation of heritage, particularly our case study ksar El-Haouita which has experienced a neglecting and depopulation due to several factors. The ksar El-Haouita is among the most famous ksour located in the south of Algeria and exactly in the region of Laghouat. It is built with simple materials and techniques of construction. The construction materials used are local materials like stones and lime found in the environmental surroundings of the ksar. The aim of this study is to identify the major causes of the degradation of ksar, also to preserve ksar El-Haouita through specific operations and to improve the tourist attractiveness of ksar El-Haouita in order to promote heritage, to convert it back into sustainable Saharan tourism. Our study based in the first place; on a theoretical underpinning which contains the notions that have a relation with our theme, the problematic and the envisaged objective, then a presentation of ksar followed by a morphological analysis accompanied by identification of the problems to identify the phenomena of damage and its disfigurement. The last step is to treat an aspect for the development of ksar, this aspect is devoted to the restitution of the defensive system (doors, ramparts, ramparts of houses and towers) of the ksar, through a diagnostic and several operations like (rehabilitation and reconstruction). The aim result of this study is to show that the revaluation of the ksar is a very vast operation and proposes interventions that allow the preservation of the ksar and also to understand the elements that help the success of interventions and to put some of the parameters considered as reference elements and basic principles for the operations on the ksar and among these operations it is (the case study, which is the restitution of the defensive system of ksar El-Haouita).

Patterns of intraspecific variation through ontogeny: a case study of the Cretaceous nautilid Eutrephoceras dekayi and modern Nautilus pompilius

Palaeontology ◽  
2020 ◽  
Vol 63 (5) ◽  
pp. 807-820
Author(s):  
Amane Tajika ◽  
Neil H. Landman ◽  
Naoki Morimoto ◽  
Kenji Ikuno ◽  
Tom Linn
Keyword(s):  
Intraspecific Variation ◽  
Nautilus Pompilius

scholarly journals Research on Perception Diversity in Intercultural Communication —With Guasha Treatment as a Case Study

2019 ◽  
Vol 9 (1) ◽  
pp. 82
Author(s):  
Qiong Ou
Keyword(s):  
Intercultural Communication ◽  
Negative Impact ◽  
Management Theory ◽  
English Learning ◽  
Uncertainty Reduction Theory ◽  
External Stimuli ◽  
Uncertainty Management Theory ◽  
Communication Study ◽  
Impact Perception

This paper aims at depicting the phenomenon of perception diversity and its negative impact on intercultural communication (hereafter referred to as IC), as well as trying to offer a corresponding solution. Perception, according to its definition, is a process by which we make what we sense into a meaningful experience by selecting, categorizing and interpreting internal and external stimuli to form our worldviews. Guasha Treatment, a movie which provides the readers with a real intercultural context, is regarded as a classic in English learning and intercultural communication study. With detailed analysis, this paper illustrates that perception diversity will hinder successful IC by causing misunderstandings in communication. Then, based on Berger and Calabrese’ Uncertainty Reduction Theory and Gudykunst’s Anxiety/Uncertainty Management Theory, empathy is chosen as a solution to reduce the negative impact perception diversity has on IC.

scholarly journals Modeling Sustainable Risks Mitigation Strategies Using a Morphological Analysis-Based Approach: A Real Case Study

2021 ◽  
Vol 13 (21) ◽  
pp. 12210
Author(s):  
Manel Elmsalmi ◽  
Wafik Hachicha ◽  
Awad M. Aljuaid
Keyword(s):  
Morphological Analysis ◽  
Risk Mitigation ◽  
Risk Identification ◽  
Mitigation Strategies ◽  
Real Case ◽  
Main Step ◽  
Supply Chain Risk Management ◽  
Study Results ◽  
Process Risk

The supply chain risk management (SCRM) is very critical to strategically support the firms to continuous success. There are, at least, three basic steps in this SCRM process: risk identification, risk evaluation, and risk mitigation (treatment). Whatever happens, the main step is risk mitigation (RM) and mainly sustainable RM. In fact, every risk must be eliminated or controlled as much as possible. The purpose of this paper is to elaborate and evaluate various RM scenarios from an initial risk identification and prioritization solution. The proposed scenario modeling technique is based on morphological analysis (MA) as an explorative scenario tool for RM. MA is used to develop a framework to proactively assess critical risk variables. Firstly, MA is employed to exhaustively create possible RM scenarios and, secondly, to assess the likelihood of each scenario. The proposed approach addresses the need for a basic rubric to help identify and choose RM approaches. A real case study is provided from the food industry to illustrate the application of the proposed approach. To handle all possible MA strategies, a dedicated MORPHOL software package is used. In addition, RM strategies are selected based on sustainability indicators. The case study results prove that MA has a considerable value for SCRM. It shows that firms can adopt multiple robust strategies in the form of a scenario describing all stages of SCRM in an integrated representation.

scholarly journals A Morphological Analysis of Neighborhood Structure—Toles and the Ritual Artifacts of the Kathmandu Valley Towns—The Case of Thimi

MANUSYA ◽  
2003 ◽  
Vol 5 (3) ◽  
pp. 40-65 ◽  
Author(s):  
Mohan Pant ◽  
Funo Shuji
Keyword(s):  
Morphological Analysis ◽  
Level Structure ◽  
Kathmandu Valley ◽  
Neighborhood Structure ◽  
Royal Court ◽  
Territorial Structure ◽  
Archaeological Work ◽  
The Town ◽  
Historical Periods

The traditional towns of the Kathmandu Valley are ingrained with varying cultural forms of different historical periods. But the paucity of documented literature and the evident difficulties conducting archaeological work on the existing settlements leave significant gaps in the knowledge of ancient and medieval towns of the Valley. This paper, through the morphological analysis of neighborhood units, known as toles, and their ritual artifacts, of one of the Valley towns—Thimi—attempts to discover the different historical layers of the settlement. In particular, the study finds that the territorial structure of the tole and its ritual artifacts such as the shrine of Ganesa, which is the symbol of a neighborhood locality, and the crossroad spirit, known as chwasa show a regular pattern in their location within the neighborhood quarter, and their distribution in the settlement. They are also found to be closely related to the settlement structure as defined by the neighborhood blocks and the street patterns. Following the morphological analysis, the study then reconstructs four historical phases, and suggests that the development of the town was regulated by the royal court. Further, through the case study of the three neighborhood units, the paper shows that totes constituted basic urban units—a transition level to the town settlement that differed from the lower level structure of the clan settlement unit.

scholarly journals FACTORS ASSOCIATED WITH GROWTH CHANGES IN "GAZELLES"

2008 ◽  
Vol 16 (02) ◽  
pp. 161-188 ◽  
Author(s):  
ETIENNE ST-JEAN ◽  
PIERRE-ANDRÉ JULIEN ◽  
JOSÉE AUDET
Keyword(s):  
High Growth ◽  
Growth Strategies ◽  
Longitudinal Case Study ◽  
Growth Opportunities ◽  
Factors Associated ◽  
Intangible Resources ◽  
Actual Growth ◽  
Growth Changes ◽  
Over Time

The goal of this paper is to identify the factors that precede and may cause sudden changes in the pace of growth of high-growth SMEs or gazelles. A retrospective longitudinal case study of seven high growth SMEs that had undergone a total of 14 sudden shifts in growth reveals that a number of events caused the changes of pace. Some were triggered by the entrepreneur's decisions while others resulted from events beyond his/her control. Management's motivation for growth was an important element and this motivation changed over time, being influenced by both success and problems associated with actual growth. The success of growth strategies also appears to depend on the firm's proximity to its client base and its ability to obtain the information required for sound decision-making. Lastly, the availability of tangible and intangible resources was found essential in allowing the company to seize growth opportunities and proximity to the business milieu may help accessing these resources.

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