scholarly journals Ontogenetic variations and structural adjustments in mammals evolving prolonged to continuous dental growth

2017 ◽  
Vol 4 (7) ◽  
pp. 170494 ◽  
Author(s):  
Helder Gomes Rodrigues ◽  
Rémi Lefebvre ◽  
Marcos Fernández-Monescillo ◽  
Bernardino Mamani Quispe ◽  
Guillaume Billet
Keyword(s):  
Relative Size ◽  
Valuable Insight ◽  
Developmental Studies ◽  
Continuous Growth ◽  
Architectural Patterns ◽  
Herbivorous Mammals ◽  
The Impact ◽  
Dental Ontogeny ◽  
Masticatory Apparatus ◽  
Lower Molar

Studying dental ontogeny in mammals can provide valuable insight on the evolution of their masticatory apparatus and their related adaptations. The multiple acquisitions of a prolonged to continuous growth of teeth in herbivorous mammals in response to high abrasion represent an intensively investigated issue. However, the ontogenetic and architectural patterns associated with these repeated dental innovations remain poorly known. Here, we focused on two case studies corresponding to distant mammalian clades, the extinct Mesotheriidae (Notoungulata), which shared some striking dental features with the extant Ctenodactylidae (Rodentia). We studied the impact of prolonged to continuous growth of molars on their occlusal complexity, their relative size and their dynamics in the jaw. We found that variations of occlusal complexity patterns are the result of paedomorphic or peramorphic heterochronic processes impacting dental crown. We showed that variations in both upper and lower molar proportions generally follow the inhibitory developmental cascade model. In that context, prolonged dental growth implies transitory adjustments due to wear, and also involves dental migration and loss when combined with molar lengthening. Interestingly, these features may be present in many mammals having prolonged dental growth, and emphasize the crucial need of considering these aspects in future evolutionary and developmental studies.

European Economies Stability Faced With Potential Outburst of Sovereign Debt Crisis. An Empirical Study Using Neural Network

2013 ◽  
Vol 12 (2) ◽  
pp. 3255-3260
Author(s):  
Stelian Stancu ◽  
Alexandra Maria Constantin
Keyword(s):  
Neural Network ◽  
Sovereign Debt ◽  
Debt Crisis ◽  
Banking System ◽  
Sovereign Debt Crisis ◽  
European Level ◽  
Continuous Growth ◽  
Economic Context ◽  
European Economies ◽  
The Impact

Instilment, on a European level, of a state incompatible with the state of stability on a macroeconomic level and in the financial-banking system lead to continuous growth of vulnerability of European economies, situated at the verge of an outburst of sovereign debt crises. In this context, the current papers main objective is to produce a study regarding the vulnerability of European economies faced with potential outburst of sovereign debt crisis, which implies quantitative analysis of the impact of sovereign debt on the sensitivity of the European Unions economies. The paper also entails the following specific objectives: completing an introduction in the current European economic context, conceptualization of the notion of “sovereign debt crisis, presenting the methodology and obtained empirical results, as well as exposition of the conclusions.

R&D Heterogeneity and the Impact of R&D Subsidies*

2021 ◽  
Author(s):  
Sigurd M⊘lster Galaasen ◽  
Alfonso Irarrazabal
Keyword(s):  
Economic Impact ◽  
Growth Model ◽  
Relative Size ◽  
Schumpeterian Growth ◽  
Size Dependent ◽  
Investment Growth ◽  
The Impact ◽  
D Investment ◽  
Model Fits

Abstract This paper studies the determinants of R&D heterogeneity and the economic impact of R&D subsidies. We estimate a Schumpeterian growth model featuring firms with heterogeneous innovation efficiencies. The model fits well the R&D investment distribution, and the frequency and relative size of R&D performers. Using the model we study the impact of a Norwegian R&D reform targeting firms with R&D spending below a certain threshold. The size-dependent subsidy increases aggregate R&D investment by 11.7%, but reduces growth and welfare. In contrast, a uniform subsidy stimulates investment, growth and welfare.

scholarly journals Detecting Convergence Trends among EU Universities

Economies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 42
Author(s):  
Maria Adamakou ◽  
Dimitris Kallioras ◽  
George Petrakos
Keyword(s):  
Methodological Approach ◽  
Basic Research ◽  
Valuable Insight ◽  
Traditional Role ◽  
University Ranking ◽  
Convergence Clubs ◽  
Development Processes ◽  
The Impact ◽  
The Empirical Analysis ◽  
Insight Into

Universities are emerging growth determinants. This is so as, in addition to the fulfillment of their traditional role in teaching and (basic) research, universities, as aptly described within the helix framework, are expected to engage in regional development processes. The paper aims to detect trends of convergence among EU universities in terms of performance. To the best of our knowledge, this topic has not hitherto been examined. The empirical analysis of the paper covers the period 2014–2021, utilizes data obtained from URAP (University Ranking by Academic Performance), and employs the methodological approach of convergence clubs. The findings of the paper provide valuable insight into both theory and policy-making. We conclude that despite the unification of EU educational space, trends of divergence among EU universities are still present, and notable divisions still remain. Consequently, this indicates that the impact of EU universities on the formation of spatial disparities across EU space is not neutral.

scholarly journals Developmental up-regulation of NMDA receptors in the prefrontal cortex and hippocampus of mGlu5 receptor knock-out mice

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Tiziana Imbriglio ◽  
Remy Verhaeghe ◽  
Nico Antenucci ◽  
Stefania Maccari ◽  
Giuseppe Battaglia ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Nmda Receptor ◽  
Metabotropic Glutamate Receptors ◽  
Adult Life ◽  
Developmental Time ◽  
Postnatal Life ◽  
Developmental Studies ◽  
Knock Out ◽  
Nmda Receptor Subunits ◽  
The Impact

AbstractmGlu5 metabotropic glutamate receptors are highly expressed and functional in the early postnatal life, and are known to positively modulate NMDA receptor function. Here, we examined the expression of NMDA receptor subunits and interneuron-related genes in the prefrontal cortex and hippocampus of mGlu5−/− mice and wild-type littermates at three developmental time points (PND9, − 21, and − 75). We were surprised to find that expression of all NMDA receptor subunits was greatly enhanced in mGlu5−/− mice at PND21. In contrast, at PND9, expression of the GluN2B subunit was enhanced, whereas expression of GluN2A and GluN2D subunits was reduced in both regions. These modifications were transient and disappeared in the adult life (PND75). Changes in the transcripts of interneuron-related genes (encoding parvalbumin, somatostatin, vasoactive intestinal peptide, reelin, and the two isoforms of glutamate decarboxylase) were also observed in mGlu5−/− mice across postnatal development. For example, the transcript encoding parvalbumin was up-regulated in the prefrontal cortex of mGlu5−/− mice at PND9 and PND21, whereas it was significantly reduced at PND75. These findings suggest that in mGlu5−/− mice a transient overexpression of NMDA receptor subunits may compensate for the lack of the NMDA receptor partner, mGlu5. Interestingly, in mGlu5−/− mice the behavioral response to the NMDA channel blocker, MK-801, was significantly increased at PND21, and largely reduced at PND75. The impact of adaptive changes in the expression of NMDA receptor subunits should be taken into account when mGlu5−/− mice are used for developmental studies.

Impact of the Cluster Spacing on Hydraulic Fracture Conductivity and Productivity of a Marcellus Shale Horizontal Well

2021 ◽  
Author(s):  
Mohamed El Sgher ◽  
Kashy Aminian ◽  
Ameri Samuel
Keyword(s):  
Hydraulic Fracture ◽  
Marcellus Shale ◽  
Technical Information ◽  
Gas Production ◽  
Production Performance ◽  
Valuable Insight ◽  
Fracture Conductivity ◽  
Fracture Properties ◽  
Gas Recovery ◽  
The Impact

Abstract The objective of this study was to investigate the impact of the hydraulic fracturing treatment design, including cluster spacing and fracturing fluid volume on the hydraulic fracture properties and consequently, the productivity of a horizontal Marcellus Shale well with multi-stage fractures. The availability of a significant amount of advanced technical information from the Marcellus Shale Energy and Environment Laboratory (MSEEL) provided an opportunity to perform an integrated analysis to gain valuable insight into optimizing fracturing treatment and the gas recovery from Marcellus shale. The available technical information from a horizontal well at MSEEL includes well logs, image logs (both vertical and lateral), diagnostic fracture injection test (DFIT), fracturing treatment data, microseismic recording during the fracturing treatment, production logging data, and production data. The analysis of core data, image logs, and DFIT provided the necessary data for accurate prediction of the hydraulic fracture properties and confirmed the presence and distribution of natural fractures (fissures) in the formation. Furthermore, the results of the microseismic interpretation were utilized to adjust the stress conditions in the adjacent layers. The predicted hydraulic fracture properties were then imported into a reservoir simulation model, developed based on the Marcellus Shale properties, to predict the production performance of the well. Marcellus Shale properties, including porosity, permeability, adsorption characteristics, were obtained from the measurements on the core plugs and the well log data. The Quanta Geo borehole image log from the lateral section of the well was utilized to estimate the fissure distribution s in the shale. The measured and published data were utilized to develop the geomechnical factors to account for the hydraulic fracture conductivity and the formation (matrix and fissure) permeability impairments caused by the reservoir pressure depletion during the production. Stress shadowing and the geomechanical factors were found to play major roles in production performance. Their inclusion in the reservoir model provided a close agreement with the actual production performance of the well. The impact of stress shadowing is significant for Marcellus shale because of the low in-situ stress contrast between the pay zone and the adjacent zones. Stress shadowing appears to have a significant impact on hydraulic fracture properties and as result on the production during the early stages. The geomechanical factors, caused by the net stress changes have a more significant impact on the production during later stages. The cumulative gas production was found to increase as the cluster spacing was decreased (larger number of clusters). At the same time, the stress shadowing caused by the closer cluster spacing resulted in a lower fracture conductivity which in turn diminished the increase in gas production. However, the total fracture volume has more of an impact than the fracture conductivity on gas recovery. The analysis provided valuable insight for optimizing the cluster spacing and the gas recovery from Marcellus shale.

Overcoming economic liminality: internationalization of B2B SME’s from a small emerging economy

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Barney G. Pacheco ◽  
Syed Akhter
Keyword(s):  
Emerging Market ◽  
Foreign Market ◽  
Emerging Economy ◽  
Foreign Market Entry ◽  
Valuable Insight ◽  
Content Type ◽  
Qualitative Research Design ◽  
Theoretical Perspectives ◽  
Internationalization Strategies ◽  
The Impact

Purpose Current research on small to medium enterprise (SME) internationalization has generated valuable insight but continues to overlook the activities of business-to-business (B2B) SMEs located in small emerging economies. This study aims to fill this gap by testing the applicability of the ownership, location and internalization (OLI) framework to understand the internationalization strategies of small B2B firms in Trinidad and Tobago, a small emerging Caribbean economy. Design/methodology/approach The study used a qualitative research design, which involved in-depth interviews with senior executives of three firms in the B2B sector who were knowledgeable about their firm’s internationalization process. Thematic analysis was then used to understand the motivations and strategies underpinning the internationalization approach adopted by each firm. Findings Contrary to the stereotype of SMEs in emerging markets as fragile enterprises, there is evidence that firms exploited the development of innovative products and processes to facilitate foreign market entry and expansion. Additionally, firms overcame resource limitations by relying on governmental ties and leveraging networking opportunities. The findings also call attention to the impact of organizational learning and the role of knowledge as a dynamic capability. Originality/value Both the context of the study and the application of the OLI framework contributes to the extant literature by yielding substantive insights into the internationalization strategies of B2B firms in a small emerging economy. The findings further highlight how the OLI framework can be supplemented by other theoretical perspectives to better understand internationalization by emerging market SMEs.

Dynamic Response of a Generic Vehicle Floor Model to Coupled Transient Loads

1996 ◽  
Author(s):  
Aaron D. Gupta
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Response Analysis ◽  
Impact Loads ◽  
Valuable Insight ◽  
Concentrated Load ◽  
Shell Elements ◽  
Transient Loads ◽  
Method Of Evaluation ◽  
The Impact

Abstract A dynamic elastic large displacement response analysis of the bottom floor of a generic vehicle hull model subjected to empirically obtained coupled blast and impact loads has been conducted using three-dimensional (3-D) shell elements in the ADINA nonlinear dynamic finite element analysis code. For the impulse-dominated problem, the impact load is a square wave step function concentrated load while the blast loads from the detonation of an explosive are a series of distributed pressure loads approximated as triangular impulse loads with linear decay and varying arrival and duration times. The 3-D numerical model has been generated using the PATRAN3 modeling code and converted to the ADINA finite element input data deck using the ADINA translator and careful inclusion of appropriate material properties as well as initial and boundary conditions. Monolithic single-layered four-noded quad shell elements were sufficient to model the bottom floor and the left- and right-horizontal and vertical sponsons as well as the lower front glacis. Although several simplifying assumptions and approximations are made during the generation of the basic floor model, material properties, and the forcing functions, the investigation gives valuable insight into the response behavior of a generic hull bottom floor to externally applied coupled blast and impact loads and provides an inexpensive nondestructive method of evaluation of the structural integrity of modern vehicles subjected to spatially varying transient loads.

Energy or carbon? Exploring the relative size of universal zero carbon and zero energy design spaces

2018 ◽  
Vol 40 (3) ◽  
pp. 319-339 ◽  
Author(s):  
Anna Parkin ◽  
Manuel Herrera ◽  
David A Coley
Keyword(s):  
Design Space ◽  
Relative Size ◽  
Building Design ◽  
Zero Energy ◽  
Software Environment ◽  
Space Forms ◽  
Regulatory Frameworks ◽  
Regulatory Standards ◽  
Zero Carbon ◽  
The Impact

One aim of zero carbon, or zero energy, buildings is to help slow climate change. However, regulatory definitions frequently miss substantial emissions, for example ones associated with the materials the building is constructed from, thereby compromising this goal. Unfortunately, including such emissions might restrict the design space, reduce architectural freedom or greatly increase costs. This work presents a new framework for examining the problem. The zero carbon/energy design and regulatory space forms a sub-space of the hyper-volume enclosing all possible designs and regulatory frameworks. A new mathematical/software environment was developed which allows the size and shape of this sub-space to be investigated for the first time. Twenty-four million building design/regulatory standard combinations were modelled and assessed using a tree classification approach. It was found that a worldwide zero standard that includes embodied emissions is possible and is easier to achieve if a carbon rather than an energy metric is adopted, with the design space twice the size for a carbon metric. This result is important for the development of more encompassing regulations, and the novel methods developed applicable to other aspects of construction controlled by regulation where there is the desire to examine the impact of new regulations prior to legislation. Practical application: As energy standards become more strict, and given the growth in non-regulatory standards (such as Passivhaus), there is the need to study the potential impact of any element of a standard on the range of designs that can be built or the materials that can be used. This work sets out a general framework and method for doing this. The approach and results will be of interest to policy makers, but also to engineers and architects wondering what the key constraints to design the adoption of various philosophies to low energy/carbon standards might have within their work. For example, the implications of the building standard (or client) requiring embodied emissions to be included or the energy balance period for renewable generation to be monthly, not annual.

scholarly journals Architectural Diversity of Submarine Lobate Deposits

2021 ◽  
Vol 9 ◽  
Author(s):  
Tim R. McHargue ◽  
David M. Hodgson ◽  
Eitan Shelef
Keyword(s):  
Turbulent Flows ◽  
Deep Water ◽  
Relative Size ◽  
Transport Pathway ◽  
Branching Points ◽  
Channel Patterns ◽  
The Impact ◽  
Source Materials ◽  
Permeability Structure ◽  
Distributary Channel

Lobate deposits in deep-water settings are diverse in their depositional architecture but this diversity is under-represented in the literature. Diverse architectures result from multiple factors including source material, basin margin physiography, transport pathway, and depositional setting. In this contribution, we emphasize the impact of differing source materials related to differing delivery mechanisms and their influence on architecture, which is an important consideration in source-to-sink studies. Three well imaged subsurface lobate deposits are described that display three markedly different morphologies. All three lobate examples, two from intraslope settings offshore Nigeria and one from a basin-floor setting offshore Indonesia, are buried by less than 150 m of muddy sediment and are imaged with high resolution 3D reflection seismic data of similar quality and resolution. Distinctively different distributary channel patterns are present in two of the examples, and no comparable distributaries are imaged in a third example. Distributary channels are emphasized because they are objectively recognized and because they often represent elements of elevated fluid content within buried lobate deposits and thus influence permeability structure. We speculate that the different distributary channel patterns documented here resulted from different processes linked to source materials: 1) a lobate deposit that is pervasively channelized by many distributaries that have branched at numerous points is interpreted to result from comparatively mud-rich, stratified, turbulent flows; 2) an absence of distributaries in a lobate deposit is interpreted to result from collapse of mud-poor, turbulent flows remobilized from littoral drift; and 3) a lobate deposit with only a few, long, straight distributaries with few branching points is interpreted to be dominated by highly viscous flows (i.e., debris flows). We propose a conceptual model that illustrates the relationship between the proportion of mud in contributing flows and the relative size and runout distance of lobate deposits. We conclude that reconciling 3D seismic morphologies with outcrop observations of channels, scours, and amalgamation zones, and simple application of hierarchical schemes, is problematic. Furthermore, when characterizing unconfined deep-water deposits in the subsurface, multiple models with significant differences in predicted permeability structure should be considered.

scholarly journals Performance evaluation of video streaming on LTE with coexistence of Wi-Fi signal

2019 ◽  
Vol 8 (3) ◽  
pp. 890-897
Author(s):  
Y. J. I. A. Yaqoob ◽  
W. L. Pang ◽  
S. K. Wong ◽  
K. Y. Chan
Keyword(s):  
Video Streaming ◽  
Network Performance ◽  
Software Radio ◽  
Radio Spectrum ◽  
Application Framework ◽  
Data Traffic ◽  
Continuous Growth ◽  
Lte Network ◽  
The Impact ◽  
Unlicensed Band

The continuous growth in mobile data traffic and limited license wireless spectrum have led to dramatically increase the demand of the radio spectrum. It is widespread the concern about the coexistence of long term evolution (LTE) and Wi-Fi in the unlicensed band. There are several techniques have been proposed to enable the coexistence of LTE and Wi-Fi in the unlicensed band, but these works are targeted on the impact of the LTE to the Wi-Fi network performance. An experiment is carried out in this work to evaluate the impact of Wi-Fi signal on the video streaming in the LTE network. The experimental test comprised of the national instrument (NI) universal software radio peripheral (USRP) 2953R that is controlled by the LabVIEW Communication LTE application framework. Extensiveexperiments are carried out under two scenarios, i.e. (1) Coexistence of LTE and Wi-Fi signal, (2) LTE signal only. Performance evaluations are carried out with different Modulation and coding schemes (MCS) values and different mode of operations, i.e. frequency division duplex (FDD) and time division duplex (TDD) mode. The results illustrated that the interference from Wi-Fi signal caused the performance degradation of the LTE network in throughput and the power received by user equipment (UE).

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